HEAT PUMPS / THE BASICS
Heat pumps don’t generate heat.
They move it.
The idea behind the modern heat pump is more than 170 years old. The clever part isn’t making heat — it’s collecting heat that already exists and moving it into your home.
01
Collect
Heat is collected from the air, ground or water outside the home.
02
Compress
Electricity powers the process that raises the temperature of the collected heat.
03
Move
The upgraded heat is transferred into the home’s heating system.
04
Repeat
The refrigerant cycle continues, moving heat rather than creating it.
NOT A NEW IDEA
Heat pumps have been a long time coming.
For many homeowners, heat pumps seem like a very modern technology. In reality, scientists and engineers have been exploring the principle for generations.
1850s
The principle
Scottish physicist William Thomson, later Lord Kelvin, developed the theoretical principles behind moving heat from a colder area to a warmer one using mechanical energy.
LATE 1800s → EARLY 1900s
Refrigeration proves the idea
Refrigeration systems demonstrated that heat could be removed from one place and released somewhere else. The obvious question followed: could the same process heat a building?
1930s
Large-scale heating
Early large-scale installations appeared in Europe. In Switzerland, engineers used heat from Lake Geneva to provide heating for public buildings.
1970s → TODAY
Efficiency becomes important
The energy crises of the 1970s renewed interest in reducing fossil-fuel use. Modern heat pumps are the result of decades of improvement in the same basic idea.
THE SIMPLE EXPLANATION
Think of a refrigerator.
Then reverse the job.
A refrigerator removes heat from inside the cabinet and releases it into the room. A heat pump uses the same basic principle to collect heat from outside and deliver it into your home.
Outside heat → Heat pump → Your home
It isn’t creating energy from nothing. It is using electricity to move existing heat.
WHERE DOES THE HEAT COME FROM?
Three main heat sources.
The heat-pump principle is broadly the same. What changes is where the system collects its heat.
01 / AIR
Air source
An air source heat pump extracts heat from the outside air and transfers it into the home’s heating system.
02 / GROUND
Ground source
Ground source systems collect heat stored in the ground using buried pipework or boreholes.
03 / WATER
Water source
Water source heat pumps can collect heat from a suitable body of water and move it into the property.
There is another option. A hybrid heating system combines a heat pump with a boiler, allowing the two technologies to work together when required.
WHY EFFICIENCY LOOKS DIFFERENT
Electricity runs the pump.
It doesn’t provide all the heat.
A traditional electric heater converts electricity directly into heat. A heat pump uses electricity to operate a system that moves additional heat from the environment.
ELECTRICITY IN
1
↓
HEAT MOVED
3–5
The exact performance depends on the system and operating conditions.
COMMON MISCONCEPTION
“But what happens
when it’s cold?”
Heat pumps are not a technology designed only for mild climates. Sweden, Norway and Finland adopted heat pumps much earlier than many countries and use them in conditions considerably colder than most of the UK.
The important issue isn’t simply whether a heat pump works in cold weather.
The design, sizing, controls, emitters and home itself all matter.
HEAT PUMPS IN THE UK
Why are we hearing so much about them now?
Heat pumps have been installed in Britain for years, but wider adoption remained limited while gas, oil and other fossil fuels dominated domestic heating.
01 Rising energy costs
02 Better heat-pump efficiency
03 Government support and the Boiler Upgrade Scheme
04 Reducing carbon emissions
05 Greater awareness of home energy efficiency
THE BIT THAT MATTERS
A heat pump isn’t automatically right for every home.
The technology is proven. But good performance depends on careful design and understanding the property it is being installed into.
Heat loss, insulation, radiators or underfloor heating, flow temperatures, hot-water requirements, controls and the behaviour of the people living in the home can all influence how well the final system performs.
KEEP EXPLORING
Understand the system
before choosing the system.
Helping with the retrofit puzzle.
Understand the home first. Then decide which technology belongs in it.