Heat pumps are best known for heating properties efficiently, but did you know they can also provide cooling? As UK summers get hotter, more homeowners and building managers are looking at heat pumps not just for warmth, but for comfort year-round.
In this article, we unpick the different types of cooling available through heat pumps — including passive, active, and comfort cooling — and explore how Air Source Heat Pumps (ASHPs) and Ground Source Heat Pumps (GSHPs) compare. We’ll also explain how your choice of radiators or underfloor heating impacts cooling performance.
Passive cooling vs active cooling vs comfort cooling
Let’s clear up the jargon first!
Passive cooling
- Available with GSHPs
- Uses the naturally cool ground temperatures to lower indoor temperatures without using the compressor – circulating chilled water.
- Very low energy use – only requires a circulation pump to work.
- However, cooling effect is limited – won’t drop your temperature like air conditioning.
Active cooling
- Can be achieved with both ASHPs and GSHPs.
- Works by reversing the heat pump cycle, like a fridge in reverse – moving heat from indoors and releasing it outside.
- More effective than passive cooling, but uses more energy than passive systems.
- Best for buildings needing regular cooling in summer.
Comfort cooling
- Often used to describe a light-touch, lower-intensity form of active or passive cooling.
- Doesn’t aim to chill like traditional air conditioning, but keeps spaces comfortable and avoids overheating.
- Ideal for homes and offices that want better summer performance without high running costs.
- Distributed via underfloor heating infrastructure.
ASHP vs GSHP for cooling
Both ASHPs and GSHPs can offer cooling, but how they do it — and how well — differs.
Ground source heat pumps (GSHPs)
- Best option for both passive cooling. Good option for active cooling.
- Consistent underground temperatures mean stable cooling performance, even during heatwaves.
- Can be used for all types of properties, including homes, apartment blocks, schools, and commercial buildings, depending on how the cooling is distributed.
- Can support cooling via fan coils, underfloor systems, or chilled ceiling panels.
Air source heat pumps (ASHPs)
- Provide active cooling only, using a reversing valve to run in cooling mode.
- Performance depends on outdoor temperature — may be less efficient during very hot days.
- An excellent solution for comfort cooling in modern homes and small businesses.
Can you cool with radiators?
Short answer: not effectively.
Radiators are designed to emit heat, not absorb it. Using them for cooling with a heat pump system is inefficient and can cause condensation.
To cool properly, you’ll need one of the following:
1. Underfloor cooling
- Pipes in the floor circulate chilled water
- Provides silent, even cooling
- Works best in well-insulated, airtight buildings
- Risk of condensation, so careful design is essential
- Supply water temperature: 17–20°C
- Thermostats able to control both heating and cooling required
2. Fan coil units (FCUs)
- Common in both homes and commercial properties
- Blows air over chilled coils and circulates cool air
- Can be wall-mounted, ducted, or hidden in ceilings
- Works well with both ASHPs and GSHPs
- Supply water temperature: 6-8°C
Overheating and Part O
The UK’s Building Regulations introduced Approved Document O (Part O) to address the growing concern of overheating in residential buildings — especially new builds and flats.
Part O aims to ensure buildings are designed to reduce overheating risk through passive means, such as:
- Window placement and shading
- Cross-ventilation
- Solar gain limitation
However, where passive measures aren’t enough, mechanical cooling systems like heat pumps can help meet compliance.
How heat pumps support Part O compliance:
- Comfort Cooling provided by heat pumps helps reduce internal temperatures during summer peaks.
- Low-carbon operation aligns with the broader sustainability goals of new homes.
- Systems like GSHPs with passive cooling or ASHPs with fan coils offer quiet, efficient alternatives to air conditioning.
When designed correctly, a heat pump cooling system can support thermal comfort targets outlined in Part O — without the energy demand of traditional air-con.
Is cooling with a heat pump worth it?
Yes — if designed correctly.
Whether it’s for a family home, a care facility, or a school building, cooling with a heat pump can:
- Improve year-round comfort
- Reduce the need for standalone air conditioners
- Lower your carbon footprint
- Integrate seamlessly with renewables like solar PV
Final Thoughts
Heat pumps aren’t just for heating. With smart design and the right setup — from underfloor pipes to fan coils — they can keep homes and businesses cool, too.
Want to explore cooling with heat pumps for your property? Whether you’re working on a new-build, retrofit, or commercial project, we’re here to help. Contact us to speak with a heat pump expert today.
