How Does A Heat Pump Work?
Understanding the Future of Home Heating
If you’re looking for an energy-efficient, low-carbon way to heat your home, you’ve likely come across heat pumps. But how do heat pumps work — and are they the right choice for your property?
In this guide, we’ll break down the science behind heat pumps, compare air source and ground source systems, and explain exactly how they extract heat from the environment to warm your home. Whether you live in Essex, Suffolk, Norfolk or London, this article will give you everything you need to know before installing a heat pump.
What Is a Heat Pump?
A heat pump is a renewable heating system that captures heat from the outside environment and moves it into your home. Instead of burning fossil fuels like gas or oil, it uses a small amount of electricity to transfer natural heat — making it highly efficient and eco-friendly.
Think of it as a fridge in reverse. Where a fridge extracts heat from the inside and pushes it out, a heat pump collects heat from the outside and moves it in.
There are two main types used in UK homes:
- Air Source Heat Pumps – extract heat from the air
- Ground Source Heat Pumps – extract heat from the ground
How Does an Air Source Heat Pump Work?
Air source heat pumps are the most popular option in the UK. Here’s a simple step-by-step breakdown:
Step 1 – Air Is Drawn In
A fan in the external unit draws in outside air — even in cold temperatures.
Step 2 – Heat Is Absorbed by Refrigerant
The air passes over a coil filled with refrigerant. This liquid absorbs the heat and evaporates into a gas.
Step 3 – Compression Increases the Temperature
The gas is compressed using an electric compressor, which significantly increases its temperature (similar to how pumping a bike tyre gets hot).
Step 4 – Heat Is Transferred Indoors
The hot gas flows into a heat exchanger and transfers its heat to your central heating system — warming your radiators, underfloor heating, or hot water tank.
Step 5 – Refrigerant Cools and Recycles
The refrigerant condenses back into a liquid and the cycle repeats.
Works in temperatures as low as -20°C Up to 450% efficient (COP of 4.5)
Ground Source Heat Pumps – A Deeper Source of Heat
While air source systems use outside air, ground source heat pumps extract heat from the soil, where temperatures remain more constant all year round.
How It Works:
- Pipes filled with refrigerant are buried in the ground (horizontal trenches or vertical boreholes).
- The refrigerant absorbs the earth’s stored solar energy.
- Heat is then compressed and delivered to your home, just like an air source system.
These are more efficient than air source systems but require more space and excavation.
Are Heat Pumps Efficient in the UK Climate?
Yes.
Modern heat pumps are designed to work efficiently even during British winters. While performance slightly reduces in colder weather, most systems installed in the UK still deliver at least 250–300% efficiency year-round.
This makes them more efficient than even the best gas boiler.
Benefits of a Heat Pump
Massively Efficient: Produces 3–4x the energy it uses
Lower Energy Bills: Cheaper to run than gas, oil, LPG, or electric heating, when designed correctly
Eco-Friendly: Cuts carbon emissions by up to 75%
Low Maintenance: Just an annual service required
Future-Proof: Ideal for the 2035 gas boiler phase-out
Grant Available: £7,500 from Boiler Upgrade Scheme (BUS)
Common Questions About Heat Pumps
Yes — they’re used in Scandinavia and Germany where it gets much colder than the UK!
Air source units produce a gentle hum (~40–50dB) similar to a fridge. Most homeowners don’t notice them.
Not always. During our technical survey, we assess your system and advise if upgrades are needed.
Why Choose a Heat Pump?
Heat pumps are the future of home heating in the UK. They cut emissions, lower bills, and are backed by government incentives. With TLC Renewables, you’re supported by over 17 years of experience across Essex, Suffolk, Norfolk and London.