Improving your EPC rating isn’t just a “box-ticking exercise” it brings real financial, comfort, legal, and long-term benefits.
Improving your EPC rating isn’t just a “box-ticking exercise” — it brings real financial, comfort, legal, and long-term benefits. It matters because, as we progress through life, our habits, and priorities tend to shift. The carefree 20-year-old who stayed up all night and partied eventually becomes someone more conscious of energy use, the environment, and personal finances. Taking small steps to look after both the planet and our own future becomes part of that natural transition. Its not only landlords and developers who are being targeted to improve energy performance of where we live but it surly come to all of us as regulations tighten.
Improving an EPC (Energy Performance Certificate) rating usually means reducing heat loss, increasing efficiency of heating systems, and incorporating low-carbon technologies. Here’s a clear, practical list of the most effective ways to improve an EPC rating in UK homes: If you NEED to improve the EPC for rental or other purposes then I would always suggest getting a qualified and experienced DEA or Retrofit assessor to perform a Pre EPC to highlight the improvements (modelling).
1. Improve Insulation (Biggest, most cost-effective wins)
Can be applied to suspended timber floors and solid floors
Reduces draughts and cold spots. Sometimes the installation method can be in a very small crawlspace.
Draught-proofing.
Low-cost, fast EPC improvement that can easily be done on a DIY level.
2. Upgrade Heating Systems.
Replace the old gas boiler with a modern condensing boiler.
Increases efficiency to 90%+. This will be getting phased out as the UK moves away from gas boilers. Each elected government always changes the goal posts, so it’s always checking current legislation if replacing a fossil fuel heating source.
Modern cylinders have better insulation and can hold the temperature of stored water for longer periods.
Replace with a heat battery, which removes standby losses and improves SAP scores (great with heat pumps and Solar)
4. Replace Windows & Doors.
Replacing old windows, especially wooden single glazed, to a more modern double/triple glazed unit can improve the EPC and also add value to the property through aesthetics and performance. Double and triple glazing can be very little difference on a EPC. You can usually tell the age of your glazing by looking for a date in the double-glazed gap or by the gap its self. Typically, the larger the gap, the newer the glazing. A good quality unit will typically have date stamped in the gap!
Homeowner Guide: Understanding and Running Your Heat Pump.
This guide is for homeowners who are considering a heat pump or who already have one installed. It explains how heat pumps work, how to run them correctly, and what good installation practice looks like.
Whether your system is air source, ground source, or water source, the principles are the same. The only difference is where the heat comes from and how it’s delivered into our homes.
One System, Different Heat Sources
All heat pumps work by moving heat, not creating it.
Air source: collects heat from outside air.
Ground source: collects heat from the ground via buried pipes.
Water source: collects heat from rivers, lakes, or groundwater.
Once the heat is collected, everything inside your home works in the same way.
Heat is upgraded using electricity.
Heat is delivered to radiators, underfloor heating, blower unit or to heat water.
The system runs slowly and efficiently.
How a Heat Pump Should Be Run.
Heat pumps are designed to provide steady background warmth, not short bursts of high heat.
Best practice.
Leave the system running continuously during cold weather.
Use lower flow temperatures than a boiler.
Avoid frequent on/off cycling.
Let the controls do the work.
If your home feels warm, but the radiators are only warm to the touch, that’s normal and correct.
1. Run Low and Steady.
A heat pump works best when it runs continuously at a low output rather than blasting heat in short bursts. Unlike traditional boilers, heat pumps are designed to maintain a stable indoor temperature over time. Steady operation improves comfort, reduces energy use, and puts less strain on the system.
2. Avoid Constant On/Off Cycling.
Frequent stopping and starting reduces efficiency and increases wear on components. A well-designed heat pump should modulate its output to match the home’s heat loss instead of repeatedly switching on and off. Longer run times at lower power are healthier for the system and cheaper to run.
3. Lower Flow Temperatures Improve Efficiency.
Heat pumps become more efficient at lower flow temperatures. Running your system at 35–45°C instead of “high boiler” style temperatures allows the heat pump to operate at its best performance. Larger radiators or underfloor heating help deliver comfortable warmth even at these lower temperatures.
4. Let the Controls Do the Work.
Smart controls and weather compensation are key to efficient heat pump operation. The system should automatically adjust its output based on outdoor conditions and the home’s heating demand. Constantly turning thermostats up and down can actually reduce efficiency and comfort.
5. Comfort Comes from Consistency.
A properly designed heat pump system delivers an even, gentle warmth throughout the home. Instead of dramatic temperature swings, you get stable comfort, lower running costs, quieter operation, and a system that lasts longer. The goal is not fast heat, it’s efficient, balanced comfort all day long.
Heating Curve (Flow Temperature Settings)
The heating curve controls how hot the water is that flows to your heating system, based on outdoor temperature. You will find your heating curve on the heat pump control panel or external monitoring devices if installed. Always discuss with installers and ask to be shown how to use/control.
Typical Curve.
Colder outside = slightly hotter water
Milder outside = cooler water
Why this matters.
Lower temperatures = higher efficiency
Higher temperatures = higher running costs
A well-set heating curve.
Keeps rooms comfortable
Avoids overheating
Maximises efficiency
This is usually set during commissioning and may need fine-tuning once you’ve lived with the system.
Weather Compensation
Weather compensation is what allows a heat pump to think ahead. An outdoor sensor monitors temperature and automatically adjusts the heating curve.
Most modern air source heat pumps come with built-in sensors on the outdoor unit to monitor ambient temperature for efficient operation, such as managing defrost cycles. While these built-in sensors measure conditions at the unit, they are often affected by the machine’s own heat, making external, wall-mounted sensors more accurate for weather compensation.
More stable indoor temperatures
No sudden hot or cold swings
Better comfort and lower running costs
If weather compensation is disabled, the system may behave more like a boiler, which reduces efficiency.
What this means in practice.
On a cold day (around –5°C), the system might send water out at ~45°C.
On a mild day (around 15°C), it may only need ~25°C.
The system adjusts continuously, not in jumps.
Outdoor Unit Location (Avoiding Recirculation)
For air source heat pumps, correct positioning is critical.
The unit must.
Have clear airflow in front and behind.
Be away from walls, corners, or enclosed spaces.
Avoid recycling its cold exhaust air.
Poor positioning can cause recirculation, where cold air is pulled back into the unit, reducing performance and increasing noise and running costs.
Isolation valves are essential for maintenance and safety.
You should have:
Valves on flow and return pipes.
Valves near the heat pump.
Valves near key components (buffer, cylinder).
These allow:
Easier servicing.
Fault isolation.
Reduced disruption if work is needed.
Missing or inaccessible valves are a common quality issue.
Anti Freeze valveShut Off ValvesPoor Insulation
MCS Standards , What Homeowners Should Expect.
In the UK, heat pumps installed under grants (BUS, ECO4) must meet MCS standards.
This includes:
Proper system design and heat loss calculations.
Correct heat pump sizing.
Suitable radiator or underfloor heating upgrades.
Weather compensation enabled.
Commissioning and handover documentation.
You should receive:
MCS certificate
User controls explanation
System settings at handover
For illustration only.
Microgeneration Certification Scheme (MCS) is a UK-based “stamp of approval” for small-scale renewable energy technology. It acts as a quality mark, confirming that products (like solar panels or heat pumps) and installers meet strict standards for safety, performance, and reliability. The MCS stamp is certifying the installers, just like Gas Safe would certify a gas engineer.
The Big Picture
Heat pumps are not just a new appliance, they are a different way of heating a home.
They work best when:
Insulation is good
Ventilation is considered
Controls are understood
The system is allowed to run steadily
Once set up properly, all heat pumps, air, ground, or water deliver the same result:
Efficient, low-carbon, comfortable heating for modern homes.
Is it a fair COP or Scop! Understanding above 100%!
Heat pump Basics.
If you’re considering replacing your current heating and hot water system with a renewable alternative, it’s essential to be aware that this can be a significant investment. In many cases, it involves a partial or complete system upgrade, as heat emitters often (though not always) need to be updated to achieve optimal flow rates.
To determine if a heat pump is suitable for your property, you can consult the UK government’s suitability guide. The MCS best practice is here.
The primary types of heat pumps used in the UK include:
ASHP: Air Source Heat Pumps.
WSHP: Water Source Heat Pumps.
GSHP: Ground Source Heat Pumps.
A hybrid system is another option to consider, where a fossil fuel-powered boiler (like gas) works alongside a heat pump. This setup can help meet increased heating demands during the colder winter months while still reducing overall reliance on non-renewable energy sources.
How Heat Pumps Work.
Heat pumps don’t generate heat — they move it. They take warmth from the air, ground, or water and bring it into your home using a clever refrigeration cycle (a bit like a fridge that removes heat from the food but working in reverse).
The Different Types of Heat Pumps.
Although all heat pumps work on the same principle, they collect heat in different ways:
Air Source Heat Pumps (ASHP) These draw heat from the outside air using a unit that looks similar to an air conditioner — because it almost is one, just working the other way around.
Water Source Heat Pumps (WSHP) These collect heat through coils or mats placed under the surface of a pond, lake, or river.
Ground Source Heat Pumps (GSHP) These use long loops of pipe buried in the ground — either horizontally about 2 metres deep or vertically down boreholes reaching around 100 metres.
Once the heat is gathered, it’s transferred into your home through radiators, underfloor heating or blower units, depending on your home’s design and comfort preference.
This technology is new to many of us, and it needs to be used a little differently.
During the heating season, it’s best to control your home’s temperature rather than demand it. In other words, let the system maintain a steady temperature instead of turning it off and on all the time. It’s more efficient (and cheaper) to let the heat pump gently adjust the temperature up or down.
Most modern systems use outdoor temperature sensors to help with this. These sensors measure the air temperature outside and tell the heat pump how much heat your home is likely to need. On mild days, the system runs at a lower level; when it’s colder, it automatically increases output. This helps your heat pump work in tune with the weather — keeping your home comfortable while using less energy overall.
Position.
Away from sleeping and noise-sensitive areas. (newer ASHPs are very quiet). Making sure the area around the heat pump is to manufacturers guidance to allow optimum airflow and service needs.
Condensation removal.
Water will come from the unit and can pool. It’s not the same as gas boiler condensate, which can be acidic, so just basic removal to soak away or drain, depending on the manufacturer’s instructions.
Radiator sizes and pipework.
Heat pumps work at lower temperatures, so a bigger surface area, ideally underfloor heating, is beneficial. (see Delta T in main section)
Insulation of property.
The better the wall and loft (or room in roof) insulation, the less heat loss.
How regular servicing is required and access requirements.
Running costs. What is the average yearly cost to run the heat pump! This can be really important, and research and information from your installer is a must.
Solar matching.
As heat pumps operate differently through the seasons, the same goes for solar. If you are having solar PV installed thinking the panels will run the heat pump, then think again. You could try to match the solar generation to the heat pumps output, which could help with running costs.
Understanding Heat Pump Efficiency: SCOP and COP.
When looking at heat pumps, you’ll often see the terms COP and SCOP. These are simply ways of measuring how efficiently your system turns electricity into heat.
COP — Coefficient of Performance.
Measures efficiency at one moment in time — usually in perfect test conditions.
For example, a COP of 4 means that for every 1 unit of electricity the heat pump uses, it provides 4 units of heat. However, real life isn’t always perfect — temperatures change, systems switch on and off, and conditions vary throughout the year. That’s where SCOP comes in.
SCOP — Seasonal Coefficient of Performance. Gives a more realistic picture of your heat pump’s efficiency over an entire heating season.
It takes into account:
Changing outdoor temperatures as the weather warms and cools.
Energy used during standby and defrost cycles.
How efficiently the system runs at different power levels.
In short, SCOP tells you how efficient your heat pump is across the whole year, not just in ideal lab conditions.
How is SCOP Is Calculated?
SCOP compares how much heat energy your system produces with how much electricity it uses:
SCOP = Total Heat Output ÷ Total Electricity Used
Example.
If your heat pump has a SCOP of 4, that means for every 1 kWh of electricity it uses, it provides 4 kWh of heat. That’s why people often say a heat pump can be “400% efficient” It’s not creating energy, just moving it very efficiently.
Privately installed or funded?
For any renewable heating project, whether funded privately or through a UK funded scheme, the current best practices, manufacturer’s instructions and relevant building regulations should be strictly adhered to. If installed on a UK grant scheme then a quality assurance program that certifies small-scale renewable energy systems and installers need to be followed, currently this is called MCS if insulation is being carried out at the same time and as part of the funding then it must meet the current PAS. Most of the time when applying for renewable funding the installation company usually has the mechanism to set up the funding and this should be explained from the start. You should NOT have to pay anything upfront or post installation unless extras are quoted and agreed. These extras could be, for instance, larger capacity water heating, radiators as required, location requirements etc.
Have a look at the funding area of the site for more information especially the changes to the ECO scheme.
Installation Guide.
The manufacturer’s instructions will highlight any regulations that are required. Currently, all electrical regulations need to be followed and documented, as is the set out by MCS if installed on a government funded scheme. Requirements are that properties are well insulated prior to the installation (fabric first approach) and full heat loss calculations are carried out to provide information to install the system to best practice.
Installing a Heat Pump to Best Practice.
A well-installed heat pump should run efficiently, quietly, and comfortably for many years. Good design, careful installation, and proper commissioning are just as important as the heat pump itself.
1. Plan and Assess the Property.
Before installation begins, the home should be properly assessed to make sure the system is suitable and correctly sized.
Key checks:
Carry out a full heat loss calculation.
Assess insulation levels and airtightness.
Check radiator sizes and suitability.
Consider hot water demand.
Identify the best location for indoor and outdoor units.
Ensure adequate electrical supply capacity.
Why it matters:
Oversized or undersized systems can lead to poor efficiency, cycling, comfort issues, and higher running costs.
2. Install the Outdoor Unit Correctly.
The outdoor unit needs good airflow, stable mounting, and careful positioning.
Best practice:
Install on a solid, level base.
Allow sufficient clearance around the unit.
Avoid enclosed spaces or restricted airflow.
Minimise vibration and noise transmission.
Position away from bedroom windows where possible.
Ensure easy servicing access.
All pipework to be fully insulated with a UV protection class of insulation.
Why it matters:
Poor placement can reduce efficiency, increase noise, and shorten system lifespan.
3. Install Indoor Components with Care.
Pipework and internal components should be installed neatly and efficiently.
Best practice:
Keep pipe runs as short as possible.
Insulate all heating pipework properly.
Avoid unnecessary bends and fittings.
Install quality valves and controls.
Ensure condensate drainage is correct.
Mount components securely and accessibly.
Why it matters:
Good pipework design reduces heat loss and improves overall system performance.
4. Integrate Properly with the Heating System.
The heat pump should work smoothly with the home’s emitters and controls.
Best practice:
Balance radiator and underfloor circuits.
Set correct flow rates.
Remove air from the system thoroughly.
Use hydraulic separation or buffers only when needed.
Configure weather compensation correctly.
Optimise flow temperatures for efficiency.
Why it matters:
A properly balanced system delivers stable comfort and lower running costs.
5. Commission the System Thoroughly.
Commissioning ensures the heat pump operates as designed.
Key commissioning checks:
Verify flow and return temperatures
Check refrigerant and system pressures
Test pumps, valves, and sensors
Confirm weather compensation settings
Check defrost operation
Measure system performance
Record all commissioning data
Why it matters:
Incorrect commissioning is one of the biggest causes of poor heat pump performance.
6. Handover and Aftercare
Homeowners should understand how the system works and how to run it efficiently.
Best practice:
Explain controls clearly.
Advise against frequent on/off adjustments.
Provide user manuals and documentation.
Register warranties.
Discuss servicing requirements.
Offer ongoing support if needed.
Why it matters:
Heat pumps work best when run steadily at lower temperatures. User understanding makes a major difference to comfort and efficiency.
Best Practice Checklist.
Correct heat loss calculation.
Properly sized heat pump.
Good airflow around outdoor unit.
Well-insulated pipework.
Balanced heating system.
Weather compensation enabled.
Low flow temperatures configured.
Full commissioning completed.
Homeowner guidance provided.
Regular servicing planned.
All warranties and registration complete.
The Benefits of Best Practice Installation.
When installed properly, a heat pump can provide:
Lower running costs
Better comfort
Stable indoor temperatures
Quiet operation
Improved efficiency
Longer system lifespan
Reduced maintenance issues
Lower carbon emissions
If hot water is being heated in storage tanks by the heat pump then steps need to be taken to protect from legionella. Stored hot water systems connected to heat pumps have cycles to heat the water at given times and a given temperature to stop the growth of Legionella bacteria.
Electrical certificates.
The two types of electrical certificates you will come across as a customer who is having any electrical work as part of installing EEM’s (energy efficient measures)
Electrical Installation.
Minor Works Certificate.
Electrical Installation Certificate.
An electrical installation certificate is the type of certificate a customer receives after an electrician has installed one or more new circuits. Other examples include a complete rewire, a replacement consumer unit or an additional consumer unit. Generally, any time electrical work is done at the consumer unit, a new installation certificate will be issued.
Minor Works Certificate.
A minor works certificate is issued after an electrician has made an alteration to an existing circuit. Minor works certificates are often used to certify work such as adding additional sockets to an existing circuit or increasing the number of light fittings in a room. It can also be where a fused spur has been installed for an appliance or boiler connection.
Final Thought.
The best heat pump installations focus on steady operation, low flow temperatures, good controls, and careful system design. A quality installation is what turns a heat pump from “just working” into delivering real comfort and efficiency for the long term.
Selecting a trustworthy installer for your heating, insulation, or renewable energy project requires careful research and due diligence.
Hiring the right professional ensures your home is safe, efficient, and compliant with regulations, and helps protect warranties, insurance, and grant eligibility.
Reputable installers are often accredited by recognised trade bodies or professional organisations. Accreditation confirms that the installer:
Meets industry standards
Has undergone proper training
Is legally authorised to perform specific types of work
NAPIT – Covers electrical and heating installations.
NICEIC – Approved contractor scheme for electrical work.
MCS – Microgeneration Certification Scheme – Required for heat pumps, solar PV, and renewable energy installations. Using accredited installers is essential for compliance, safety, and accessing grants or incentives, such as the UK Boiler Upgrade Scheme (BUS) or ECO4 funding.
Find a Qualified Retrofit Installer
Select the work you want carried out on your home.
This guide shows the qualifications, certifications and governing bodies
a competent installer should hold.
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Being registered with the above does not always mean the work is checked by the certification company, It usually shows competence within the field of current health & safety practices and current regulations. Remember that if you have any work carried out at your property either on a grant scheme or self financed you should be covered by consumer rights. The citizen’s advice is always a good place for information.
Some of the below will help with your journey in finding trades.
If you feel you are vulnerable.
Try to get a family member or neighbour to sit in with you when getting quote visits, also maybe designate someone else to deal with the process.
Ask for Recommendations.
Seek recommendations from friends, family, or colleagues who have recently had similar work done. Personal recommendations can be invaluable in finding trustworthy installers.
Read Reviews and Testimonials.
Check online reviews and testimonials on platforms like Trustpilot, Checkatrade, or Which? Trusted traders and google reviews. These platforms often provide insights into the quality of work and customer satisfaction, But please be aware that not all reviews can be genuine!
Obtain Multiple Quotes.
Don’t settle for the first installation company you find. Obtain quotes from multiple companies for comparison. Be wary of quotes that are significantly lower than others, as they may indicate subpar workmanship or the use of inferior materials. If you are applying down a grant funded route, then be weary of being promised the earth or pushed into signing up. Any decent installation company should keep you at ease and answer all your questions honestly.
Verify Insurance and Guarantees.
Ensure that the installation company/individual has adequate insurance coverage, including public liability insurance, to protect you and your property in case of accidents or damage. Also, inquire about any guarantees or warranties offered for the work they perform.
Check for Compliance with Regulations.
Certain types of work, such as electrical or gas installations, require compliance with specific regulations and safety standards. Verify that the installers you choose are appropriately qualified and registered to carry out such work.
Communicate Clearly.
Communicate your expectations clearly, including timelines, budget constraints, and any specific requirements you may have. Reputable installers will be transparent and be responsive to your needs.
Trust Your Instincts.
If something feels off during your interactions with installers or if they seem unwilling to provide necessary information or documentation, trust your instincts and consider looking elsewhere.
Get Everything in Writing.
Once you’ve decided on an installation company, make sure to get all agreements, including costs, timelines, replacement of fixings (window sills, skirting etc) redecorating and scope of work, in writing. This helps protect both parties and ensures clarity and accountability throughout the project.
External Wall Insulation can significantly change the look and function of your property, so it’s important to understand the process in detail before work begins. Confirm what insulation system will be used, its thickness, and the finish type (e.g. render, brick-slip, or cladding). Ask how the installers will deal with fixtures and features such as satellite dishes, alarm boxes, lights, air vents, overflow pipes, and external taps—these should all be properly removed, extended, and reinstated, not simply covered over.
Openings and Details.
Discuss how the system will accommodate windows, doors, and sills, as these may need to be extended or replaced to ensure proper sealing and to prevent water ingress. Check that drip beads, stop beads, and corner trims will be installed neatly and to specification for a high-quality, durable finish.
Ventilation and Airflow.
Make sure that ventilation and airbricks are not blocked or removed. Ask how they will be extended through the insulation system to maintain airflow and prevent damp or condensation. Obtain a clear ventilation specification, and ensure the finish matches or complements your property’s appearance. For homes with fireplaces or open flues, ask about spillage testing and combustion ventilation to ensure safety and compliance.
Groundworks and Damp-Proof Course.
Confirm that the insulation will finish above the damp-proof course (DPC) and that appropriate base trims and drainage channels will be installed. The system should not bridge the DPC unless designed to do so, as this can lead to moisture problems. Ensure that any existing damp or drainage issues—including blocked gutters or damaged downpipes—are addressed before insulation begins.
Aesthetics and Boundaries.
If your home is part of a terrace, semi-detached, or adjoins another property, ask how the system will terminate at party walls, fences, or neighbouring structures. Ensure that detailing will be neat and watertight. For listed buildings or properties in conservation areas, confirm that planning permission or building consent is in place. Regulations change so what may of been permitted last year may not be now, and visa versa!.
Safety and Compliance.
For homes with chimneys, fireplaces, or combustion appliances, ask about spillage tests and combustion ventilation to ensure safety after the installation.
Documentation and Clean-Up.
Request written details of all materials, fixings, and finishes, including manufacturer names and warranty information. Confirm that all waste and debris will be removed and agree on a timeline for completion and clean-up.
Finally, ensure you have full contact information for everyone involved in the project, including the installation team, project or site manager, and—if installed through a UK grant scheme, the Retrofit Coordinator responsible for oversight and compliance.
Internal Wall Insulation (IWI) and Room-in-Roof Considerations.
Disruption and Reinstatement.
Internal Wall Insulation can be highly disruptive, often requiring the removal of features such as skirting boards, window sills, coving, door frames, electrical sockets, light fittings, and radiators. Confirm that your installer will reinstate all removed items and specify whether they will be restored or replaced. Ensure that qualified tradespeople—such as joiners for woodwork and plumbers for wet work—will carry out these tasks, and get this commitment in writing.
System and Detailing.
Ask which insulation system will be used and how the installer plans to treat complex areas such as coving, cupboards, or meter locations. For room-in-roof spaces, confirm that any loft or eaves hatches will be properly insulated and professionally fitted, not simply boarded over. If you use roof storage, ensure this area remains accessible and structurally suitable for use once insulated.
Check that all electrical, alarm, TV, satellite, and internet cables will be correctly routed through the insulation and fully reinstated afterwards.
Ventilation and Safety.
A ventilation system should be installed as part of the works. Obtain a detailed specification to confirm it meets high standards of performance and finish. For homes with fireplaces or open flues, ask about spillage testing and combustion ventilation to ensure safety and compliance.
Pre-Installation Checks and Documentation.
Before work begins, inspect the external walls, damp-proof course, gutters, and downpipes. Any existing issues must be identified and either rectified by the installer or formally agreed with you in writing, as they can compromise insulation performance and cause long-term problems.
Finally, confirm that all debris will be cleared and agree on a timeline for completion and cleanup. Request full contact details for everyone involved, including the office manager, installation team (noting if subcontractors are used), and—if the work is part of a UK grant scheme—the Retrofit Coordinator overseeing the project.
Cavity Wall Insulation considerations.
Scope and Drilling.
Confirm that all suitable wall areas will be insulated, which may involve internal drilling. Discuss in advance where drilling will occur and what materials will be used to fill and finish the holes afterwards to ensure a neat appearance.
Garages and External Finishes.
For attached but unheated garages, talk through insulation options—particularly if shelving, cupboards, or other fixtures will need to be removed or adjusted. When drilling into external walls, ask what colour of mortar will be used to fill the holes, especially on rendered or painted surfaces. Confirm whether installers will repaint or touch up the finish to match the existing façade.
Material and Clean-Up.
Find out exactly which insulation material is being used and take the time to research its properties and suitability for your home. Clarify whether the installation team will be responsible for cleaning up spills, dust, or debris, and have this commitment documented in writing. If you have outdoor features such as ponds or livestock areas, inform the installers so they can take precautions against overspill.
Ventilation and Safety.
If new ventilation is required, request a clear specification and ensure all installations are completed to a high standard of finish. For homes with fireplaces or open flues, ask about spillage tests and combustion ventilation to maintain safety and compliance.
Pre-Installation Checks and Aftercare.
Inspect external walls, damp-proof courses, gutters, and downpipes before work begins. Any existing damp or drainage issues must be resolved first, as they can undermine the effectiveness of the insulation and lead to long-term problems. Finally, confirm that all debris will be removed and agree on a clear timeline for completion and cleanup—especially important for removal and refill projects.
It can be challenging to assess conditions beneath the floor unless you have a basement. Confirm the type, thickness, and support method of insulation being installed, and ensure all accessible areas will be covered. If floorboards need to be lifted, be aware this can cause damage—ask whether replacements will match the original boards to maintain appearance and consistency. Take pre-installation photographs for reference.
Cross Ventilation.
Adequate underfloor ventilation is essential. Make sure any existing vents or decorative grilles are retained or replaced with alternatives that are both functional and visually appropriate. Request written confirmation of how cross-flow ventilation will be maintained or improved, including details of the units being installed. The system should allow sufficient airflow to prevent moisture buildup and stop water ingress.
Basement Insulation.
If a basement is being insulated, ask about fire safety compliance and verify that all work adheres to current building regulations. It’s worth doing your own research for added assurance.
Ventilation and Safety.
If a ventilation system is included, obtain a detailed specification and confirm it will be installed to a high standard. For properties with fireplaces, request information on spillage tests and combustion ventilation to ensure safety and compliance.
Pre-Installation Checks and Cleanup.
Inspect external walls, damp-proof courses, subfloor ventilation, and rainwater systems (gutters, downpipes, etc.) before work begins. Any existing damp or drainage issues must be resolved first, as they could compromise the insulation and cause long-term damage. Finally, confirm that all debris and waste materials will be removed and agree on a clear timeline for completion and cleanup.
Ask which insulation materials will be used—such as spray foam, mineral wool, or PIR boards—and make sure you understand their limitations and how they may affect your property’s insurance or mortgage eligibility.
Access and Storage.
Discuss how the installation will impact access to essential services in the loft, such as boilers or solar inverters, and whether storage areas will still be usable or need adjustment.
Electrical Safety.
If you have recessed down lights, these must be properly protected to prevent air leakage and potential overheating. Suitable covers or fire-rated caps should be used. For electric showers or other circuits with cables running through the loft, ensure proof is provided that the cables are not buried within insulation, as this can cause overheating.
Pipework and Loft Hatches.
All exposed water pipes should be fully insulated. The loft hatch should also be insulated and drought-proofed to a professional standard—avoid makeshift solutions like loosely stapled insulation.
Ventilation and Timber Protection.
Adequate airflow in the loft is essential to prevent condensation and protect the roof timbers. Confirm that ventilation will be maintained or improved as part of the work.
Whole-Home Ventilation and Safety.
If a new ventilation system is being installed, request a clear specification to ensure it meets high-quality standards and finishes. For homes with open fireplaces, ask about spillage tests and combustion ventilation to ensure safety and compliance.
Most combination boilers need a larger gas supply pipe than older systems, often requiring an upgrade from the meter. Before installation, confirm the planned gas pipe route to avoid unnecessary external runs if an internal route is possible. If the pipe must run outside, ensure it’s properly clipped and installed in line with regulations.
Heating Controls.
Discuss your heating controls and where the thermostat will be located. It should be positioned in a room without a thermostatic radiator valve (TRV) or any secondary heat source such as a fire or cooker, to ensure accurate temperature readings.
Condensate Drainage.
All condensing boilers produce condensate that must be drained safely. Ideally, this drainage point should be located indoors. If the condensate pipe must run externally, it needs to be insulated with Class 0 lagging. Confirm the type of insulation being used and how it will be secured and supported.
System Clean and Preparation.
Ensure all debris will be removed during installation and clarify when this will happen. Most boiler manufacturers require a full system flush before fitting the new unit—this is essential. Make sure the installer carries it out, and ideally, observe the process. The correct use of cleaning and inhibitor chemicals is vital for system health, and their use should be recorded in the Benchmark log (the boiler’s installation and service record). Ask for a copy for your files.
Warranty and Guarantees.
Confirm both the manufacturer’s warranty and the installer’s guarantee, particularly regarding leaks and workmanship. Once the boiler is installed, it’s a good idea to call the manufacturer directly after a few weeks to confirm that your warranty is fully registered and active.
You may already know the direction your property faces, but installers might suggest positioning the panels differently. This could be due to access issues, roof condition, or other practical constraints. However, the optimum orientation delivers the best performance, so make sure your installer prioritises efficiency over convenience.
Inverter Location.
The inverter should be installed somewhere easy to access for inspection, servicing, and maintenance, while also being protected from the elements. Some models are suitable for outdoor installation, provided they’re shielded from direct sunlight and rain. If you live near the coast, ask about corrosion resistance and whether additional protection is needed.
Monitoring Meter.
The generation meter (monitoring meter) should be positioned where it can be easily read and checked regularly. Make sure it’s visible enough to monitor energy production and detect early signs of faults (for example, if it isn’t blinking in daylight). Some installers may say it has to go in loft if inverter is also installed there, but dont allow, have it somewhere you can read and check.
Paperwork and Certification.
Confirm the expected timescales for all necessary documentation, including MCS certification, DNO approval, and any paperwork your energy supplier may require.
Warranties and Guarantees.
Clarify the warranty terms and guarantee lengths for all equipment. Make sure you know who to contact in case of faults or system failure.
Get Everything in Writing.
Once you’ve decided on a installation company, make sure to get all agreements, including costs, timelines, and scope of works, in writing. This helps protect both parties and ensures clarity and accountability throughout the project.
Ask your installer to explain which make, model of heat pump is being fitted and why it’s suitable for your property. Confirm that the system has been properly sized for your home, an undersized or oversized unit can reduce efficiency and increase running costs. Request a full design calculation (MCS or equivalent) showing heat loss per room, flow temperatures, and emitter sizing. Ask what refrigirant is used within the pump (R32, R290 etc). Ask about hybrid systems to help in the winter months.
Outdoor Unit Location.
The external unit should be positioned where airflow is unrestricted, but noise and vibration will not affect you or neighbours. It must sit on a stable, level base (often a concrete pad with anti-vibration plinth) and be clear of obstructions such as fences or foliage. If located near boundaries, confirm it meets local noise regulations and planning guidance. It should meet manufactures clearances for optimum airflow. For coastal or exposed locations, ask about corrosion-resistant finishes and protective coatings. (if within 2000m from the coast this is a must)
Internal Components.
Confirm where the indoor cylinder, buffer tank, and controls will be located. These should be easily accessible for servicing and maintenance, with pipework neatly installed and insulated. Discuss how existing systems—such as radiators or underfloor heating will be adapted or replaced, and ensure the flow and return pipe sizes are appropriate for the new system.
Condensate and Drainage.
Heat pumps produce condensate water, particularly in colder weather. This must be drained safely away from the base unit, ideally into a proper soakaway or drain. The pipework must not freeze, so confirm that suitable insulation and gradients are in place. The condensate produced is not the same a a combustion boiler so it is not acidic.
Electrical and Controls.
Ensure the electrical supply is adequate and compliant with regulations, with a dedicated isolator switch. Ask about the control system whether it will use smart thermostats, weather compensation, or load compensation and how to use these features for maximum efficiency.
Groundworks and Protection.
If installing a ground source heat pump, confirm the ground loop layout (horizontal trenches or boreholes), and request documentation of where pipes are buried for future reference. For air source units, confirm that rainwater runoff from roofs won’t drip onto the unit and that the area around the base remains well-drained and clear of standing water.
Warranties, Maintenance, and Support.
Ask for details of warranties and service agreements for both the equipment and installation. Heat pumps require annual servicing to maintain performance and warranty validity, so ensure you receive a maintenance schedule and the installer’s or manufacturer’s contact details.
Paperwork and Certification.
Ensure you receive all necessary documentation, including MCS certificates,DNO notifications, and user manuals. These are essential for warranty registration, grant schemes (such as the Boiler Upgrade Scheme), and resale value.
Cleanup and Completion.
Confirm that all debris and packaging will be removed and agree on a clear completion timeline. Obtain written contact details for the installation company, lead installer, and if installed through a UK grant scheme the Retrofit Coordinator responsible for the project.
Installing an Air-Source Heat Pump (ASHP) near the coast, what to know, rules to follow, and what manufacturers recommend.
Living by the sea is lovely, but if you’re fond of sand dunes and salty air, you should consider some important guidance on siting a heat pump because chances are that your heat pump isn’t as fond of the salty air as you!.
Permitted development rules in England were changed in 2025 and now rely on MCS 020 (and its updates) for many domestic ASHP installs. (mcscertified.com).
Regulations and planning, the essentials.
From late May 2025 amendments to permitted development rules made it easier to install ASHPs without planning permission in many domestic cases, but the installation must comply with the Microgeneration Certification Scheme (MCS) planning/install standards (MCS-020 / MCS-020a) and other PD (Permitted Developments) conditions (size limits, noise, locations, etc.). Installers should demonstrate compliance with MCS documentation where PD is claimed. Always check for conservation areas/listed buildings/existing planning conditions which can still require consent.
Noise & siting: Latest MCS guidance contains sound-calculation and siting obligations installers will use to show an installation meets PD/no-nuisance rules. Where neighbours are close (typical in coastal terraces), installers often need to demonstrate predicted noise at neighbouring façades is acceptable.
What manufacturers say about coastal installations.
Few manufacturers publish official minimum coastal setback distances, most talk about protecting units from direct sea winds or salt spray, not precise statutory distances. Its up to you to engage with the installer as your warranty could become null and void if the recommended distances are breached.
Below is a quick snippet to what recommendations are from some manufacturers out there. Please do your own research, but hopefully these guides will help.
Mitsubishi (Ecodan) — offers coastal protection variants or finishes on outdoor units designed to reduce corrosion from salt spray. Some coastal models are explicitly designated by a suffix (e.g., “BS”) and are recommended for closer distances to the sea. If you live on an exposed shoreline, ask for a coastal model or treatment. (Mitsubishi)
Daikin — installer guidance and Daikin support note that additional treatments are available to protect heat-exchanger surfaces and external components; the UK support/solutions teams can advise on protective options for marine environments. Always follow the installation manual for clearances and service access. (Daikin)
Vaillant (aroTHERM) — the installation/operation manual highlights safe siting, condensate discharge (frost-free routing), and service access. The manual includes requirements for frost protection of condensate and clearances for maintenance — important in coastal locations where extra exposure may affect frost/condensate behaviour. (Vaillant Pro)
Grant – Newer Models (Aerona³ and Aerona 290): The most recent models are designed to be suitable for installation in coastal areas without any special anti-corrosion treatment required at the time of installation.
NIBE — stresses correct system design, insulation and pre-install site assessment; manufacturers commonly advise that coastal sites need more frequent checks and may benefit from coastal finishes or local corrosion protection applied to the heat exchanger and painted surfaces. The warranty statement says upto 1km from coast is classed as coastal.(NIBE)
Aftermarket corrosion protection — products like Blygold surface-coatings are commonly used by installers to give added protection to heat-exchangers and fins where manufacturer coastal options are not available or for retrofit protection. Discuss warranties and any effects on heat-transfer with supplier/installer before applying after market coatings. (blygold for example)
Bottom line – Ask the Installer whether a coastal-protected variant exists. If there is an approved coastal option, prefer that over improvised fixes
Practical siting, mounting and flood considerations (coastal specifics).
Distance and exposure: “Close to the sea” What is this! 1 mile, 2 km, 100 yards? Manufacturers often publish guidance/diagrams showing recommended distances for untreated units, if you’re in the spray zone (wind-driven salt), insist on a coastal model or coating. Regulations may be in place that manufacturers specify distances from the coast, but If I’m having a heat pump installed, I think i can gauge if I’m near the sea!
If its windy, salty and you can see the sea, chances are you want the unit protected.
Elevation for flood zones.
If the property is at flood risk, raise the outdoor unit above the expected flood level (or base flood elevation). Industry guidance and consumer guides recommend elevating critical outdoor equipment on a secure platform at least above likely flood levels, this reduces risk of mechanical and electrical damage. The .GOV website can give you some useful info on potential flooding. (other areas of the UK are linked though the .gov site)
Maintenance & service recommendations for coastal installations.
Just keep an eye on the unit, do not cover and hinder airflow. Ideally, get it serviced yearly, and the engineer should give it a good clean and check areas of potential corrosion.
Discuss warranty & service plans: Ask whether coastal exposure requires a different warranty or service plan. Some manufacturers’ standard warranties may exclude damage from excessive salt spray/unusual exposure unless a coastal variant or approved coating is used.
A homeowner’s checklist (before you book the installation).
Get a site survey from an MCS-certified installer who has experience with coastal sites. They should reference MCS-020 and local PD conditions.
Ask the installer to confirm: Is a coastal model needed? If so, which model/suffix? If not, what protective measures will be used (manufacturer-approved coating, bespoke enclosure, maintenance plan)? Ask for manufacturer confirmation in writing.
Check flood risk (gov.uk flood maps / local authority). If at risk, include elevation and secure fixings in the design.
Noise & neighbour check: Ask installer to provide predicted noise levels at neighbours and show compliance with PD / local rules (especially important in terraces and holiday areas).
Warranty & coatings: Confirm that any after market coating (e.g., Blygold) is compatible with the unit and does not void warranty — ideally use manufacturer-approved options.
A heat battery is a device that stores heat energy and releases it when your home needs it.
As the UK moves towards cleaner and smarter ways to heat our homes, one technology is starting to make a name for itself: heat batteries.
You might have seen them mentioned alongside heat pumps in recent government home upgrade plans. But what exactly are they, and why are they becoming popular?
You’ve probably heard of old type electric storage heaters maybe you’ve even come across one before. They store heat inside metal cabinets using heavy bricks, using cheaper electricity at night when most people were asleep and demand was low.
Heat batteries work on a similar idea, but with modern materials and smarter design. They store energy as heat when electricity is cheaper or more available, and then release it later when you need hot water or heating. Below is a video from sunamp.Heating battery basics.
So what is a heat battery?.
A heat battery is a device that stores heat energy and releases it when your home needs it. Think of it as a modern alternative to a hot water cylinder, but smaller, faster, and far more efficient.
Instead of storing litres of hot water, a heat battery stores energy using materials like phase-change materials (PCMs) or ceramic blocks. These absorb and hold heat at high temperatures, then release it on demand to heat water or contribute to space heating.
How Does a Heat Battery Work?
A heat battery typically works in three simple steps:
Charge.
The battery is heated using electricity from your heat pump, solar PV, or the grid — often at off-peak times when energy is cheaper and cleaner.
Store.
The system holds that heat with minimal loss, often for many hours. Phase-change batteries “lock in” heat as they melt and solidify, similar to how ice packs work — just at much higher temperatures.
Delivery.
When you open a tap or your heating system calls for hot water, the battery releases stored heat instantly. You get quick, consistent hot water without waiting for a tank to warm up.
Why Are Heat Batteries Becoming Popular?
Smaller Footprint.
A heat battery can be up to 5–10 times smaller than a traditional hot-water cylinder. Great for flats, small homes, or anywhere space is tight.
Faster Recovery
They recharge quickly, making them ideal for busy households needing lots of hot water.
Works well With Heat Pumps.
Heat pumps run best at steady, low-demand times. Heat batteries let you store heat produced overnight or when your heat pump is running efficiently.
Perfect with Solar Panels.
Solar PV can charge the battery during the day, giving you almost-free hot water in the evening.
Lower Bills with Smart Charging.
Pairing a heat battery with:
off-peak tariffs
smart meters
solar generation can significantly cut running costs.
What Can a Heat Battery Replace?
In many homes, a heat battery can replace:
Traditional hot water cylinder
An immersion heater
In some setups, parts of a boiler system
They are particularly useful in heat-pump-only homes or homes switching to low-carbon heating.
Are They Eligible for Grants?
Yes, the government recently confirmed that heat batteries now qualify for a £2,500 grant under the Boiler Upgrade Scheme. This brings their upfront cost down significantly and makes them competitive with traditional hot-water systems.
Should You Install One?
A heat battery is ideal if:
You have (or plan to install) a heat pump
You want to save space
You’re looking to manage energy costs using solar PV or off-peak tariffs
Your home has high hot-water demand
You want a future-proofed, low-maintenance system
You need to improve a EPC rating on a property using old storage types.
They’re less suited to very large households with extreme hot-water usage — a large cylinder may still be a better fit in those cases.
Final Thoughts.
Heat batteries are one of the most exciting upgrades currently available for UK homes. They’re compact, efficient, low carbon, and cost-effective — and with the new grant support, they’re more accessible than ever.
Fabric First Approach, What It Is and Why It Matters!
The fabric first approach is built on a simple principle: reduce heat loss from the building before upgrading heating systems or adding renewables.
“Fabric” is just another term for walls, roof, floors and windows.
Instead of installing a high-tech heating system in a leaky home, fabric first aims to fix the building first, then optimise how it’s heated.
Why Fabric First Became the Gold Standard.
For years, fabric first has been the backbone of UK retrofit policy (including PAS 2035), and for good reason.
1. It Reduces Energy Demand at Source.
By improving insulation and airtightness, the home simply needs less heat to stay comfortable.
Lower energy bills.
Less reliance on heating systems.
Reduced carbon emissions.
This is fundamental—you can’t efficiently heat a home that constantly loses heat.
2. It Improves Comfort and Health
Fabric improvements don’t just save energy, they change how a home feels.
Warmer surfaces (no cold walls).
Fewer draughts.
Reduced risk of damp and mould.
More stable indoor temperatures.
These benefits are well documented, including improved physical and mental wellbeing.
3. It Futureproofs the Home.
A well-insulated building works better with any heating system.
Heat pumps perform more efficiently.
Smaller systems can be used.
Lower running costs long-term.
In other words, fabric first makes every future upgrade more effective.
4. It Supports a “Whole House” Approach
Fabric first encourages thinking about the home as a system:
Insulation.
Airtightness.
Ventilation.
Heating.
All designed together, not as bolt-on measures.
So Why Is It No Longer the “Only” Answer?
Despite its benefits, fabric first is no longer seen as the universal gold standard, especially when viewed through the lens of net zero.
This shift is strongly influenced by research such as the “Every Home Counts” review (which highlighted quality, whole-house thinking, and unintended consequences) and more recent academic work like “Fabric first: is it still the right approach?”.
The Key Challenges.
1. Net Zero Has Changed the Priority.
Fabric first was developed when all heating was fossil fuel-based.
Today, we can decarbonise heat directly using technologies like heat pumps.
Research shows that:
In some homes, switching to low-carbon heating alone can achieve major carbon reductions.
Fabric upgrades, while beneficial, are not always essential for decarbonisation.
2. Time and Scale Constraints.
Deep fabric retrofit (e.g. solid wall insulation, floors, airtightness upgrades):
Is expensive.
Is disruptive.
Requires skilled labour.
At current rates, rolling this out across all UK homes would take decades.
This creates a real issue: If you wait for “perfect fabric,” you may delay urgent carbon reduction.
3. Diminishing Returns.
Many homes have already had:
Loft insulation.
Cavity wall insulation.
What’s left is:
Harder.
More expensive.
More invasive.
The cost-benefit balance becomes less attractive at scale.
Balancing a central heating system properly is what separates a working” system from an efficient, comfortable, and compliant one
1. Pre-checks are critical.
Before touching lockshield valves:
System fully bled (no air)
Correct system pressure.
Pump operational and correctly set.
All TRVs fully open.
Room thermostat calling for heat.
Boiler at normal operating temperature (flow ~70°C typical).
If these aren’t right, balancing will be inaccurate.
2. Identify radiator order
You need to know flow sequence:
First radiators = closest to boiler
Last radiators = furthest away
This matters because closer radiators naturally take more flow.
3. Fully open all lockshield valves
Remove caps (if still on!).
Open all lockshields fully (anti-clockwise).
4. Measuring temperatures.
Measuring temperatures when balancing radiators can feel a bit daunting at first, but a digital thermometer is inexpensive and easy to use. Most are simple point-and-click devices, allowing you to quickly take readings from the flow and return pipes.
For greater accuracy, clamp thermometers can be used, although they tend to be more expensive.
The flow and return pipes can be installed either way, but typically the TRV is fitted on the flow side. If you’re unsure, it’s worth checking while the system is heating up one side will warm up faster, helping you identify the flow
True affordability is not achieved by cutting corners or reducing upfront costs alone,
Designing any heating or renewable system—whether it’s a heat pump, electric storage, gas boiler, unvented system, underfloor heating, radiator configuration, must begin with a single guiding principle: efficiency comes first.
True affordability is not achieved by cutting corners or reducing upfront costs alone, but by designing systems that perform at their highest potential. When efficiency leads the design, it naturally shapes long-term affordability—lower energy use, reduced running costs, and greater overall value.
In essence, affordability should never dictate efficiency; rather, efficiency should define affordability.
The Science.
We’re human—and often stubborn. It’s natural to trust what we can see and what we believe, even when the science tells a deeper story.
But when it comes to our homes and keeping them warm, the science is vast and uncompromising. Facilities like the Energy House in Salford constantly test and thermally model real-world conditions, while manufacturers subject materials to extremes of heat and cold to understand exactly how they retain or lose energy.
Before any legitimate product reaches the market, it undergoes rigorous testing and must achieve strict certification standards—whether UK or European. Only then is it assigned performance values, allowing it to be accurately modelled within properties and used to meet UK regulations.
In short, what may seem simple on the surface is backed by an immense depth of science, testing, and proven performance.
Sizing For Our Homes.
When a new heating system or existing one is being specified or upgraded there are many factors to take into consideration. When I first started as a heating engineer it would be standard to go to a plumbers merchand and order a combi and 5 radiators as a standard heatpack which is no way to size for a property. Lets look at some examples of how we would size a property for heating. We will discus hot water requirements later.
Electric storage heaters can be hard to correctly size as they use stored cheaper overnight energy to heat properties during the day, things like work patterns, occupation and social factors like pre payment meters can all play a part.
For the next section we are looking at primary heating using gas or heat pumps.
Heat Loss.
Are we robbing Peter to pay Paul—or neither? It’s a great expression, especially when you think of it in heating terms: are we unintentionally drawing warmth from our neighbours, if we even have any?
Understanding heat loss starts with the basics—identifying losses through walls and floors, considering the size of the property, and defining the level of heat demand required through radiators etc. Once we understand our heat loss not only do we understand our radiator positions (underfloor obvious) but also the optimum balance of energy use to comfort levels.
We calculate our heating requirement by looking at room sizes, then adjusting it based on how well our homes holds heat. Older homes, poor insulation, and exposed walls increase heat loss — while insulation and neighbouring properties reduce it.
Q = Heat required (Watts) This is the size of heating you need.
V = Room Volume (m³) Length × Width × Height.
F = Base Heat Loss Factor (from property age) Older homes lose more heat.
M = Modifiers (construction, insulation, exposure, etc.) Adjusts for real-world conditions.
Heat Loss & Heating Design Tool
Indoor temp
Outdoor temp
System type
We need to determine the required heat output in watts, as modern radiators and heating systems are rated this way (traditionally it was in BTUs). To do this, measure the room’s length, width, and height—giving you three figures. Multiply these together to get the volume. Then apply a heat loss factor, followed by a final adjustment or modifier (see below).
So now you know a rough heating output required for our room we now need to understand Delta T (ΔT)
What ΔT Means
ΔT (Delta T) = the temperature difference between:
Average radiator water temperature
Room temperature
Radiators are rated for heat output at a standard ΔT, typically:
ΔT50 → Water 70°C, Room 20°C → ΔT = 50°C
ΔT60 → Water 75°C, Room 15°C → ΔT = 60°C
ΔT30 → Water 35°C, Room 20°C → ΔT = 30°C (common for heat pumps)
Radiator outputs are listed for ΔT50 (standard UK value) If you run a heat pump at 35–45°C, ΔT drops → radiator output drops → room may feel cold
Radiator
Output @ ΔT50
Output @ ΔT30
K2 600×1000
1800W
~1050W
UK Radiator Selector Tool (we have used stelrad radiators for this)
A Publicly Available Specification (PAS) is a document that defines good practice standards for a product, service, or process.
PAS 2035/2030 are linked frameworks that outline best practices for retrofitting homes in the UK to enhance energy efficiency. While PAS 2030 focuses on the quality of the installation processes, PAS 2035 ensures that the retrofit is appropriate for the building as a whole. Current PAS documents can be downloaded here.
It’s a crucial component of the UK government’s strategy to boost building efficiency and reduce carbon emissions. Adopting a “whole house” approach, PAS 2035 considers the home’s environment, occupancy, and the homeowner’s objectives, ensuring that retrofit projects address key aspects such as insulation, ventilation, occupancy, and building fabric to support long-term sustainability.
Although not a regulation, PAS 2035 is a publicly available specification (PAS), developed to address shortcomings of previous schemes following the Each Home Counts Review.
PAS 2035 compliance is mandatory for all publicly funded projects, including those supported by the Energy Company Obligation (ECO), and Warm Home Fund. We also have a route called licence plus which is run by Trustmark which does not need coordination as part of its process!. This is mainly aimed at self funding retrofit but using installers that are roughly following the current PAS process. Whichever mechanism is to be used, the property occupier should request details of which route the process follows pre-install.
PAS 2035 has its strengths, but also notable limitations. If everyone in the supply chain, assessors, coordinators, designers, and installers adheres strictly to the process, the framework should work effectively. However, lapses in monitoring and inspection can lead to issues. Unfortunately, “technical monitoring” for most UK schemes is minimal, and no longer performed by Ofgem, meaning that failings can go unnoticed, leaving property occupiers unaware of potential problems. Hopefully this will change with future consultations.
The retrofit process involves a range of participants, including canvassers, lead generators, social marketeers, assessors, designers, coordinators, installers, and a limited number of technical monitoring agents. This complexity, along with regulations, updates to rules and red tape, can create confusion and drive up costs.
The standard will transition from PAS 2035:2019 to PAS 2035:2023 in March 2025.
Protecting the Property Occupier!
PAS 2035 outlines several requirements for both pre and post installation stages. One of its most valuable aspects is the involvement of a retrofit coordinator throughout the process.
The coordinator’s primary role is to safeguard the interests of the property and its occupants, ensuring the retrofit is carried out effectively and sustainably. In an ideal scenario, the retrofit coordinator would operate independently, free from any conflicts of interest and most importantly in my opinion has performed in the retrofit assessment area. However, this level of impartiality is often difficult to achieve in practice.
By understanding the processes outlined below, you’ll hopefully gain the knowledge needed to ask informed questions and engage with some confidence at various stages of your retrofit journey.
In practice.
If the property / occupants have met the requirements of a funded scheme, then the installation or funding company will arrange for a retrofit coordinator to instruct a visit from a retrofit assessor. The coordinator is the first in the process as this is the stage that the property classification is usually identified (traditional, non-traditional etc.)
The assessor should try to get a picture of what the typical energy use entails and also what is expected by improving the property. Lots of photographs will be taken as an EPR (energy performance report) will be produced at the end. This is basically a reference EPC (energy performance certificate) but does not get published on the central register. (when EEM work is completed, a new EPC should be produced, ideally the original assessor as they will have the original data)
Some quick guidance on what the assessment entails and why!
First things are age and condition. This is to allow a retrofit coordinator to classify the property and create a plan that allows a fabric first approach that works with the natural balance of the property and highlights all potential issues.
Existing Ventilation in wet rooms photographed and noted. This is because all insulation packages require moisture to be controlled post installation. Some insulation situations require upgrades due to the design and current regulations.
Existing background ventilation photographed and noted. This is because all insulation packages require the replenishment of air post installation. Some insulation situations require upgrades due to the design and current regulations. Installers may use a pulse or blower test may be performed to validate if upgrades to background ventilation are necessary.
Fuel burning appliances noted. This is especially relevant with open flued appliances like gas, wood/coal burning fires etc. Ventilation requirements for combustion may need to be installed or verified adequate, especially after extraction units have been added or improved.
Whole footprint of property measured, including all windows/glazed doors. This allows to distinguish what is a “heat loss area” in more detail, and also potential solar gains.
Plenty of images of outside. This is to show the condition of building elements, including damp course and drainage services (gutters, downpipes, soil pipes).
Access to all rooms are required as is the loft space, basements and visual inspections of all external walls and areas. All ventilation present will be recorded and door undercut measurements should be taken. The assessment can take longer if more than one installation is being carried out, i.e. wall insulation, loft, and heating.
A report is then generated to give a rating of the properties’ energy performance from “A (very good) to a (G) very poor”. Information is then made available to the retrofit coordinator. All data is uploaded to the *Trustmark data warehouse, which forms a property plan and can be accessed by involved parties.
The coordinator will then look at all the data to see if improvements need any special design attention and intervention due to condition, age of property and location. If all looks OK then a ventilation strategy will be put in place depending on installation requirements. Some other documents are required, like a medium term improvement plan, which will create future scenario’s for improvements.
A retrofit designer will need to be consulted to design the proposed installation measure(s) if deemed necessary. We can take designers of certain measures as being members of a trade body. For example, a Gas Safe engineer installing a gas boiler, a SWIP trained installer performing IWI to a traditional non-heritage building, MCS accredited installer for solar and heat pumps.
A professional member of a Chartered Institute will be required, especially on buildings with heritage values or interacting insulation systems (wall and floor insulation being installed together, for example). It is up to the retrofit coordinator to validate that the designers and installers are all suitably qualified.
* The TrustMark Data Warehouse was created to address several recommendations in the Each Home Counts review commissioned by the Government in 2015.
The retrofit plan is executed.
This is what the installers are expected to perform to meet the current PAS. Each measure (installation or improvement) will have its own route and requirements, and brief information be found on each section within this site. The plan will provide steps for the current and potentially future improvements. A fabric first approach should always be used, this means insulation before any heating works need to be carried out. Soft touches should also be part of the fabric first approach like heating controls, draught proofing and low energy lighting.
The occupants should be informed of all work. It should be the co-ordinator and installers who contact the occupiers to inform them of the process that the retrofit project will follow. Dates, times, and conditions required will need to be discussed and agreed upon. This may include removal of furniture to prevent damage or the arrangement of alternative living arrangements throughout the works (especially on internal wall insulation). It may include preinstall remedial works to the property structure or minor repairs like broken windows, failing of rainwater removal (poor guttering) and wall pointing.
Get all this information in writing or in an email to reference at a later date if required. Make notes of Installers contact details, coordinators, and assessors names and numbers. This can be invaluable if you need to contact anyone involved in the process. You can do research on installers, co-ordinators, assessors and designers here as they all need to be Trustmark registered.
The Installation.
Once agreed and a plan has been discussed, the installation will begin. If an insulation measure is being installed, then validation is required that either the current ventilation is sufficient or insufficient. The assessment would have highlighted any shortfalls, and the installers may ask to perform an air tightness test. This can be carried out using a pulse test, this may be performed to allow installers a way of emitting undercuts and background ventilation from the installation, but controlled ventilation is always a good way to manage moisture. The ventilation should always be installed or upgraded first, or at least core vents and wiring set in place if wall insulation being installed.
The *retrofit coordinator should make a site visit if the measure is deemed high risk which includes IWI, EWI, UFI, FRI, PHI and RIR. (*this will be a mandatory requirement from early 2025) The next stage will be the installation phase of the main improvements.
*Due to time and location factors, the retrofit co-ordinator may employ a remote coordinator to feedback information after or during site visit.
The Handover.
Depending on the complexity of the installation, the duration can range from a single day to several weeks. This timeline should have been discussed and documented during the early planning stages. Before signing off on the work completed by the installation company, ensure you are fully satisfied that all agreed tasks have been completed to your expectations. Additionally, verify that any damages have been repaired or compensated. Make sure you have received all necessary handover documents, including warranties, guarantees, compliance certificates, insurance policies, gas certificates, and electrical certificates. Some certificates and warranties may come via post or email after the installation, if this is the case then ask for written clarification that they will be provided. All these documents are part of the works and may be needed if selling the property or for insurance purposes.
Insurance Backed.
To be PAS 2030 certified, installers must have an Insurance Backed Guarantee provider to ensure their customers are protected. They must also have adequate insurance coverage, including liability insurance, to protect homeowners.
What is an insurance backed guarantee? Installers will provide their own written workmanship guarantee (this is very important to get a copy of in case of any poor installations). This will outline a guarantee period, during which the installer will return and fix any faults resulting from faulty workmanship. The insurance backed guarantee only comes into effect if the original installation company ceases trading through lets say bankruptcy!. Ask for details of the company providing the guarantee, and then do your research.
All Insulation installed under PAS.
Each insulation installation will follow the same route as regards with ventilation on PAS. This should be explained by the retrofit coordinator and the installers. The basics are that background ventilation (usually trickle vents) will be provided unless an air permeability test is performed and validates the need to omit from the installation. Wet room ventilation is always required, but can vary with different insulation situations. (see below) If PIV (positive input ventilation) is being installed, then request details of why this choice is being taken, installers or retrofit coordinator will be able to guide you. (PIV will need maintenance, and it is placed in your loft space).
Some insulation situations like the property not being 100% insulated (bathrooms and kitchens being omitted due to fixture removal difficulty) then the extract ventilation may need to be a dMEV system to mitigate risks of condensation.
Pre-installation building inspection (PIBI)
The Retrofit Installer should undertake a pre-installation inspection using a competent person, this means a person or persons who have relevant industry qualifications. The inspection shall be undertaken at a level of detail sufficient to confirm that the specified energy efficient measure can be safely and effectively installed at the designated location. Particular attention shall be given to potential moisture build up as a result of the installation and taking into account the fire safety of the dwelling and the functionality and/or safety of installed services (gas, electricity, water, telecommunications, etc.)
Technical Monitoring.
Technical monitoring is a form of auditing that highlights a set of given questions on compliance. This is not performed by the installation company, but they may have their own regime of quality control. The funders (energy companies) will use these reports to highlight and hopefully rectify failing. Sadly, this shows that even with all the rules and hierarchy within the process of PAS, failing still arise. More on technical monitoring here.
