Do Heat Pumps Cool Homes in Summer?

Why UK homeowners are asking this question

Most conversations about heat pumps in the UK focus on winter heating. Will they keep the home warm? Will they reduce energy bills? Will they work in older properties?

But as UK summers become hotter, another question is becoming increasingly relevant:

Can heat pumps cool homes in summer?

The UK recorded 40.3°C for the first time in 2022, and overheating is becoming a growing concern in homes that were originally designed to retain heat, not release it.

For homeowners, landlords and housing providers, this means retrofit design is no longer just about staying warm in winter. It is also about keeping homes comfortable and safe during hotter summers.

Can a heat pump cool your home?

The answer is - sometimes.

Some heat pumps can cool homes, but not all systems are designed to do so.

Heat pumps work by moving heat from one place to another. In winter, an air source heat pump takes heat from outside air and transfers it into the home. Some systems can reverse this process in summer, removing heat from inside and transferring it outside.

This is called reversible heat pump cooling.

Whether it is suitable depends on:

• the type of heat pump

• the heating and cooling distribution system

• the property layout

• insulation, ventilation and solar gain

• whether cooling has been designed into the system from the start

A heat pump should not be assumed to provide cooling unless it has been specified and installed for that purpose.

Air-to-water vs air-to-air heat pumps

Most UK domestic heat pumps are air-to-water systems. These usually connect to radiators, underfloor heating or hot water cylinders.

Some air-to-water heat pumps can provide cooling, but standard radiators are not designed to cool rooms effectively. There can also be condensation risks if pipework or surfaces become too cold.

Cooling is generally more practical with:

• underfloor cooling

• fan coil units

• chilled ceiling systems

• systems specifically designed for cooling

Air-to-air heat pumps are more commonly associated with cooling. These systems transfer warm or cool air directly into rooms through indoor units, working in a similar way to air conditioning while also being able to provide heating.

However, air-to-air systems do not replace ventilation. Fresh air, moisture control and indoor air quality still need to be considered.

Why cooling is becoming part of retrofit thinking

Historically, UK retrofit has focused on reducing heat loss. Insulation, airtightness and better windows all help lower energy demand in winter.

But hotter summers mean homes also need to be assessed for overheating risk.

This is especially important in properties with:

• large south or west-facing windows

• top-floor rooms

• limited cross ventilation

• poor shading

• high airtightness

• vulnerable occupants

The goal of retrofit should be year-round comfort, not just lower winter heating demand.

Can insulation make overheating worse?

Good insulation can help slow heat entering a home during hot weather, particularly through roofs and walls.

However, overheating can become worse if insulation and airtightness improvements are installed without proper ventilation or solar gain control.

Common issues include:

• heat entering through large windows and becoming trapped

• limited night-time ventilation

• poor mechanical ventilation

• lack of external shading

• airtight homes with no purge ventilation strategy

What about solar panels and heat pumps?

Solar PV and heat pumps can work well together, particularly during sunny periods when electricity generation is high.

Solar panels can help power household appliances, ventilation systems and, where suitable, cooling systems. However, this depends on the design of the system and how electricity is used throughout the day.

For the best results, solar PV, heat pumps, batteries, ventilation and fabric improvements should be considered as part of a whole-house strategy.

Are heat pumps eligible for grants?

In England and Wales, the Boiler Upgrade Scheme currently provides grants towards eligible low-carbon heating systems, including air source and ground source heat pumps.

Homeowners should always check current grant rules and eligibility before making decisions, as funding criteria can change.

Installations normally need to be carried out by an MCS certified installer to qualify for funding.

Do you need planning permission for a heat pump?

Many domestic air source heat pumps can be installed under permitted development rights, provided specific conditions are met.

However, planning rules can be more complex for:

• listed buildings

• conservation areas

• flats

• leasehold properties

• homes with limited outdoor space

• installations close to neighbouring properties

Noise, location and system size also matter, so it is always worth checking the planning position before installation.

Should you install a heat pump just for cooling?

Usually, no.

A heat pump should be part of a wider strategy for heating, hot water, comfort and carbon reduction.

If your home overheats, the first step should be to understand why. In many cases, passive measures may be more appropriate, such as:

• external shading

• improved ventilation

• loft insulation

• solar gain control

• night-time purge ventilation

• reducing internal heat gains

Cooling may be useful in some homes, but it should not be the first or only response.

The future of heat pumps and summer comfort

As UK summers become warmer, heat pumps are likely to play a bigger role in year-round home comfort.

But they should not be selected in isolation. A good retrofit strategy considers the full building, including insulation, airtightness, ventilation, glazing, shading and occupant use.

At Target Green, we believe retrofit should create homes that are warmer in winter, cooler in summer and healthier throughout the year.

How Target Green Can Help

Heat pumps can play an important role in improving energy efficiency and supporting year-round comfort, but they should not be selected in isolation. The best results come from understanding the building first.

At Target Green, we help homeowners, landlords and housing providers assess whether a heat pump is suitable as part of a wider retrofit strategy. Our team considers fabric performance, insulation levels, ventilation, overheating risk, solar gain and system design to ensure any upgrade is practical, efficient and properly integrated.

Whether you are considering an air-to-air system, an air-to-water heat pump, or a wider retrofit programme, we can help you understand the right approach for your property.

If you are planning improvements and want to make sure the system is designed around the building, not just the technology, get in touch with Target Green to start the conversation.