{"id":5242,"date":"2026-10-03T09:53:13","date_gmt":"2026-10-03T09:53:13","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/stage\/?page_id=5242"},"modified":"2026-10-13T13:46:01","modified_gmt":"2026-10-13T13:46:01","slug":"all-about-epcs","status":"publish","type":"page","link":"https:\/\/mywarmhome.co.uk\/stage\/all-about-epcs\/","title":{"rendered":"All about EPCs"},"content":{"rendered":"\n
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EPC \/ MY WARM HOME<\/p>\n\n\n\n

Understanding your EPC.<\/h1>\n\n\n\n

Understand the data. Reduce heat loss. Choose improvements that suit your home.<\/p>\n<\/div>\n\n\n\n

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01<\/p>\n\n\n\n

Understand<\/h3>\n\n\n\n

Read the certificate and check the evidence behind it.<\/p>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Identify<\/h3>\n\n\n\n

Know how the walls, floors and roof are built.<\/p>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Reduce<\/h3>\n\n\n\n

Cut unnecessary heat loss and plan ventilation.<\/p>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

Improve<\/h3>\n\n\n\n

Compare suitable upgrades before spending money.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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An Energy Performance Certificate brings together information about your home’s construction, insulation, heating, hot water, lighting and renewable energy systems. Understanding that information helps you choose improvements that suit the property and reduce the energy needed to keep it comfortable. The most important part of the EPC is that it has been assessed correctly.<\/p>\n<\/div>\n\n\n\n

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EPC EXPLAINED<\/p>\n\n\n\n

What does EPC data tell you?<\/h2>\n<\/div>\n\n\n\n
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A domestic EPC shows a current energy rating from A to G, a potential rating and recommended improvements. The rating is calculated using standard assumptions about occupancy and use.
It does not come from your actual energy bills, and it cannot predict exactly what your household will spend.<\/p>\n\n\n\n

The familiar energy efficiency rating is based on modelled energy costs. Carbon emissions are a separate result. A measure can reduce emissions or improve comfort without producing the largest increase in EPC points.<\/p>\n\n\n\n

An assessor records the home’s dimensions, age and construction, together with details of insulation, windows, heating, controls, hot water and other relevant systems. Different extensions and building parts can have different construction and insulation levels.<\/p>\n\n\n\n

\u201cAssumed\u201d usually means the calculation uses a prescribed default where direct inspection or acceptable documentary evidence is unavailable. It does not prove that insulation is absent. \u201cN\/A\u201d against a floor or roof does not automatically mean it has been left out of the calculation.<\/p>\n\n\n\n

Check the assessment date, address, floor area and descriptions before relying on an old certificate. Work completed since the assessment will not appear automatically. Keep installation records and photographs of concealed insulation so an assessor can check whether they meet the evidence requirements.<\/p>\n\n\n\n

Source: Government guide to domestic EPCs<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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RDSAP 10<\/p>\n\n\n\n

What changed with RdSAP 10?<\/h2>\n<\/div>\n\n\n\n
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RdSAP means Reduced Data Standard Assessment Procedure. It is used to assess existing homes from a site survey, with prescribed assumptions where a full construction specification is unavailable.<\/p>\n\n\n\n

RdSAP 10 was introduced on 15 June 2025. It brought more detailed window measurements and glazing inputs, finer insulation thickness options for walls, roofs and floors, more detail for rooms in roofs, expanded ventilation inputs, additional renewable technology options and the ability to use suitably evidenced air pressure test results.<\/p>\n\n\n\n

These changes give assessors more ways to describe the property. They do not remove every assumption. A newer assessment can produce a different result because of changes in the method, evidence or recorded details, even when the home itself has not changed. Compare the underlying information as well as the letter rating.<\/p>\n\n\n\n

Sources: Government explanation of SAP and RdSAP<\/a>, Elmhurst’s overview of RdSAP 10 changes<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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WALL CONSTRUCTION<\/p>\n\n\n\n

Walls: construction determines the options<\/h2>\n\n\n\n
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01<\/p>\n\n\n\n

Cavity walls<\/h3>\n\n\n\n

Cavity walls have two separate layers, usually an outer layer of brick or stone and an inner layer of brick or concrete blocks. Wall ties connect the layers, with a gap (the cavity) between them.<\/p>\n\n\n\n

For domestic EPC assessments, cavity walls are recorded as a cavity wall construction, with the insulation status identified separately.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Solid walls<\/h3>\n\n\n\n

Solid walls have no cavity to fill. They can be built from brick, stone, concrete blocks or cob (an earth-based material). Solid brick walls often use a bonded pattern, where bricks laid across the wall\u2019s thickness to tie the brickwork together.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Timber-frame walls<\/h3>\n\n\n\n

Timber frame walls contain a structural timber frame, often with insulation between its timber studs. The outside may be finished with brick, rendered boards, timber cladding or other materials, so appearance alone does not reliably identify the construction.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

System-built and other non-traditional walls<\/h3>\n\n\n\n

System-built walls use a construction system, often involving prefabricated concrete panels, a steel frame or other manufactured components. Their outer finish may conceal the underlying structure, so appearance alone does not reliably identify the construction.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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FLOOR CONSTRUCTION<\/p>\n\n\n\n

Floors: look below the surface, if you can?<\/h2>\n\n\n\n
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01<\/p>\n\n\n\n

Suspended timber floors<\/h3>\n\n\n\n

Have boards and joists over a ventilated void. Insulation can be fitted between the joists, with attention to draughts and support. Underfloor ventilation must remain effective to protect the timber. Look for vents outside below the damp course.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Solid floors<\/h3>\n\n\n\n

Often contain a concrete slab. Insulation may be added above it or incorporated during replacement. Floor height, doors, thresholds and moisture protection affect the design and disruption. Do vents exist outside at floor level? do we have a small step into the property?<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Suspended concrete floors<\/h3>\n\n\n\n

Including beam-and-block construction, require a suitable system for their particular build-up. Floors over garages, outside air or unheated spaces also need attention. A carpet or decorative floor finish is not equivalent to a designed floor insulation layer.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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ROOF CONSTRUCTION<\/p>\n\n\n\n

Roofs: where is the insulated boundary?<\/h2>\n\n\n\n
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01<\/p>\n\n\n\n

Pitched roofs with an unheated loft<\/h3>\n\n\n\n

Commonly insulated at ceiling level. Coverage and continuity matter: gaps, compressed material and an untreated loft hatch reduce performance (these areas are not inputted into a RDSAP assessment). Keep eaves ventilation clear and provide raised boarding where storage is needed.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Rooms in roofs<\/h3>\n\n\n\n

Have sloping ceilings, dwarf walls and other surfaces around the heated space. Insulating only the remaining loft floor leaves much of this boundary untreated. Think loft conversion or dorma bungalow. Non visible insulation will always be as built unless documentation exists.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Flat roofs<\/h3>\n\n\n\n

Need a designed insulation and moisture-control arrangement. Roof renewal can provide an opportunity to improve insulation, but the position of insulation and the condition of the structure must be considered together. Insulationwill always be as built unless documentation exists.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

Source for floor and roof construction principles: Energy Saving Trust insulation toolkit<\/a>.<\/p>\n<\/div>\n\n\n\n

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EPC EXPLAINED<\/p>\n\n\n\n

Insulation: material, thickness and installation<\/h2>\n<\/div>\n\n\n\n
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Mineral wool, rigid foam boards, blown materials and wood-fibre products have different properties and applications. Thickness alone does not establish thermal performance: thermal conductivity, continuity, fixings, gaps and the complete construction all matter.<\/p>\n\n\n\n

A U-value describes heat transfer through a building element in W\/m\u00b2K. A lower U-value means less heat passes through each square metre for the same temperature difference. Thermal bridges at junctions can still lose heat and create cold surfaces even where the main wall or roof is insulated.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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EPC EXPLAINED<\/p>\n\n\n\n

Heating, water and controls<\/h2>\n<\/div>\n\n\n\n
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Boilers<\/strong> burn fuel to heat water for radiators, underfloor heating or domestic use. The appliance, fuel, efficiency, storage, distribution and controls affect the assessment. A boiler charachteristics and rating can be found here<\/a>. <\/p>\n\n\n\n

Heat pumps<\/strong> transfer heat from air, ground or water. Their performance depends on design, flow temperature, emitters and operation. A room-by-room heat loss calculation is needed for system sizing; the EPC alone is insufficient.<\/p>\n\n\n\n

Direct electric heaters<\/strong> turn electricity into heat at the point of use. Storage heaters<\/strong> store heat for later use and depend on suitable charging controls and tariffs. Neither should be treated as having the same performance as a heat pump. Communal heating<\/strong> supplies heat from a shared system. Its assessment depends on the system information and applicable methodology.<\/p>\n\n\n\n

A programmer sets heating times. A room thermostat regulates temperature where it senses it. Thermostatic radiator valves regulate individual radiators; zoning can provide separate control for different areas. Weather and load compensation can adjust heating operation to demand. Smart controls are useful where they add appropriate functions, but an app alone does not guarantee extra EPC points. <\/p>\n\n\n\n

Hot water also matters: the source, cylinder insulation and controls can affect energy use. Record what is actually installed and provide product details where available.<\/p>\n\n\n\n

Source for heating design: Energy Saving Trust heat loss guidance<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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HEAT LOSS<\/p>\n\n\n\n

Why heat loss matters<\/h2>\n<\/div>\n\n\n\n
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Heat escapes from our homes through walls, floors, roofs, windows, thermal bridges and air movement. Our heating systems must replace this lost heat to maintain a comfortable temperature. Reducing heat loss can improve comfort and lower energy bills.<\/p>\n\n\n\n

However, no two homes lose heat in exactly the same way<\/strong>. Detached houses may have four exposed walls, while mid-terraced properties might only have two. Extensions, garages and neighbouring properties all influence how heat moves through a building.<\/p>\n\n\n\n

Not Every Wall Is a Heat Loss Wall<\/h4>\n\n\n\n

Heat naturally moves from warmer areas to colder ones. A wall facing the outdoors will generally lose more heat than one shared with a heated neighbouring property.<\/p>\n\n\n\n

Think of the saying \u201cRobbing Peter to pay Paul.\u201d<\/em> In a terraced house, you might benefit from your neighbour’s heating as warmth passes through the shared wall. Of course, if your home is warmer, you could be heating theirs instead!<\/p>\n\n\n\n

Some party walls can also lose heat through hidden cavities and air movement.<\/p>\n\n\n\n

Why This Matters for Your EPC<\/h4>\n\n\n\n

A good energy assessor understands how buildings work, not just how to measure them.<\/strong><\/p>\n\n\n\n

Identifying exposed walls, shared boundaries, unheated spaces, partiallyheated spaces and different construction types is essential for an accurate EPC assessment.<\/p>\n\n\n\n

Understanding where heat escapes helps identify worthwhile improvements, reduce unnecessary spending and make your home more comfortable.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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EPC EXPLAINED<\/p>\n\n\n\n

Which improvements should come first and why?<\/h2>\n<\/div>\n\n\n\n
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Every home is different, so there is no single package of improvements that works for everyone.<\/strong> Whether you’re a homeowner looking to reduce bills or a landlord aiming to improve your EPC rating, it’s important to spend your money wisely.<\/p>\n\n\n\n

Here’s a sensible approach:<\/p>\n\n\n\n

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  1. Start with your EPC.<\/strong> Check your existing certificate or arrange a new assessment. Look at what’s already installed, what’s missing and where improvements could make a difference.<\/li>\n\n\n\n
  2. Fix problems first.<\/strong> Damp, leaks, damaged walls and poor ventilation should be addressed before making energy improvements. An EPC doesn’t assess the overall condition of a property, but there’s little point insulating a wall if you’re simply covering up an existing problem. Fix the cause, not just the symptoms!<\/strong><\/li>\n\n\n\n
  3. Look at the simple improvements.<\/strong> Loft insulation, heating controls, hot water cylinder insulation and LED lighting can be relatively inexpensive ways to improve efficiency. However, their impact on your EPC will vary.<\/li>\n\n\n\n
  4. Consider bigger insulation upgrades.<\/strong> Cavity wall, solid wall, floor and roof insulation can significantly reduce heat loss. Always consider the cost, disruption and potential effects on ventilation and moisture before committing.<\/li>\n\n\n\n
  5. Get the heating right.<\/strong> A new boiler or heat pump isn’t automatically the best answer. The heating system needs to suit the property. Proper heat loss calculations and energy modelling can help identify the most suitable options.<\/li>\n\n\n\n
  6. Explore solar panels.<\/strong> Solar PV can help improve your EPC rating and reduce electricity bills. However, roof condition, orientation, shading and available space all matter. Battery storage should be considered separately based on your electricity usage.<\/li>\n\n\n\n
  7. Check the results before spending.<\/strong> This is particularly important for landlords working towards a target EPC rating. Improvements don’t always deliver the points you expect, and their individual benefits cannot simply be added together. An accredited assessor can model different options to help you choose the most cost-effective combination. Ask us about EPC improvement modelling.<\/a><\/li>\n<\/ol>\n\n\n\n

    Spend Wisely, Not Necessarily More<\/h3>\n\n\n\n

    Replacing every window or installing an expensive heating system might sound like a good idea, but neither is guaranteed to provide the best return.<\/p>\n\n\n\n

    The cheapest route to a better EPC rating isn’t always the best route to a better home and the most expensive improvements don’t necessarily deliver the biggest benefits.<\/strong><\/p>\n\n\n\n

    The key is finding the right balance between cost, energy savings, comfort and EPC performance<\/strong>.<\/p>\n\n\n\n

    For homeowners, that means a warmer, more efficient property. For landlords, it means protecting your investment, improving tenant comfort and planning for energy efficiency requirements without unnecessary expense.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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    PLAN YOUR NEXT STEP<\/p>\n\n\n\n

    Start with the home. Then choose the improvements.<\/h2>\n<\/div>\n\n\n\n
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    Get practical advice on EPC information, heat loss and suitable retrofit improvements.<\/p>\n\n\n\n

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    Contact My Warm Home<\/a><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    EPC \/ MY WARM HOME Understanding your EPC. Understand the data. Reduce heat loss. Choose improvements that suit your home. 01 Understand Read the certificate and check the evidence behind it. 02 Identify Know how the walls, floors and roof are built. 03 Reduce Cut unnecessary heat loss and plan ventilation. 04 Improve Compare suitable […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"pagelayer_contact_templates":[],"_pagelayer_content":"","footnotes":""},"class_list":["post-5242","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/pages\/5242","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/comments?post=5242"}],"version-history":[{"count":23,"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/pages\/5242\/revisions"}],"predecessor-version":[{"id":5404,"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/pages\/5242\/revisions\/5404"}],"wp:attachment":[{"href":"https:\/\/mywarmhome.co.uk\/stage\/wp-json\/wp\/v2\/media?parent=5242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}