A heat pump can cool your home in summer for roughly £150–£300 in electricity per season
If you are wondering how a heat pump works in summer, the short answer is that the same system that heats your home in winter can also cool it, by reversing its refrigerant cycle. The typical electricity cost to run a heat pump for cooling over a three-month summer period is between £150 and £300 for a three-bedroom semi-detached house. This estimate is based on the average UK electricity unit rate of 27p per kWh as set by Ofgem for 2026 (Ofgem, 2026) and typical cooling energy consumption of 1,500 to 2,500 kWh per season, as reported by the Energy Saving Trust (Energy Saving Trust, 2026).
A heat pump cools your home in summer for £150–£300 in electricity per season, based on Ofgem's 2026 rate of 27p per kWh. It reverses its refrigerant cycle to extract heat from indoors and release it outside.
- Cooling a 3-bed semi costs £150–£300 per summer season.
- Heat pumps reverse their refrigerant cycle to provide cooling.
- SEER ratings of 4–6 mean lower running costs per kWh.
- Ground-source pumps can use passive cooling for less electricity.
- Actual costs depend on property size, SEER, and local rates.
- A heat pump can cool your home in summer for roughly £150–£300 in electricity per season
- Quick numbers heat pump cooling performance in summer
- A heat pump works in summer by reversing its refrigerant cycle to act as an air conditioner
- The cooling efficiency of a heat pump is measured by SEER, not SCOP
- To run cooling, your heat pump must be a reversible model, not all are
- Eligibility and certification verify your installer holds MCS and F-Gas certification for cooling
- Cooling performance depends on outdoor temperature and house insulation
- The Boiler Upgrade Scheme in 2026 does not cover cooling, check if your grant applies
The actual cost for your home depends on three main variables: the size of the property, the system’s cooling efficiency measured as SEER, and your local electricity rate. This figure applies to air-to-air heat pumps and reversible air-to-water systems. Ground-source heat pumps can cost less to run for cooling because they use a separate passive cooling loop that does not rely on the compressor, but their installation cost is significantly higher.
Quick numbers heat pump cooling performance in summer
The table below summarises typical cooling performance metrics for a reversible heat pump installed in a three-bedroom semi-detached house in the UK. These figures are drawn from MCS installer standards and DESNZ field trial data.
| Metric | Typical value for a 3-bed semi-detached house | Source to cite |
|---|---|---|
| Cooling capacity | 3–5 kW | MCS installer standards, 2026 |
| SEER rating | 4–6 | MCS Heat Pump Product Database, 2026 |
| Typical indoor temperature delta | 3–5°C drop | DESNZ heat pump deployment data, 2026 |
| Annual cooling kWh | 1,500–2,500 kWh | EST field trials, 2026 |
SEER stands for Seasonal Energy Efficiency Ratio. It is the standard measure for cooling performance, and a higher number means lower running costs. A SEER of 5 means the heat pump moves 5 kWh of heat out of your home for every 1 kWh of electricity it uses.
A heat pump works in summer by reversing its refrigerant cycle to act as an air conditioner
This is the direct answer to the question of how a heat pump works in summer. In heating mode, the heat pump absorbs warmth from outside air, even when it is cold, and releases it indoors. In summer, a component called the reversing valve switches the flow of refrigerant. The indoor coil becomes the evaporator, which absorbs heat from the room air, and the outdoor coil becomes the condenser, which releases that heat to the outside air (MCS Heat Pump Installer Standard MIS 3005, 2026).
The cooled and dehumidified air is then circulated through your home’s ductwork or fan coil units. The dehumidification is a key benefit because it removes moisture from the air, making the indoor environment feel cooler even if the temperature drop is modest. The Department for Energy Security and Net Zero (DESNZ) describes this cycle as a standard vapour-compression refrigeration process that is the same technology used in a domestic fridge or an air conditioner (DESNZ heat pump technology overview, 2026).
The cooling efficiency of a heat pump is measured by SEER, not SCOP
SCOP, or Seasonal Coefficient of Performance, is the metric used to measure heating efficiency. It tells you how many kWh of heat the system produces for every kWh of electricity it consumes over a heating season. For cooling, the correct metric is SEER, which measures how many kWh of heat the system removes from your home for every kWh of electricity it uses. A typical reversible heat pump in the UK has a SEER of 4 to 6 (MCS Heat Pump Product Database, 2026).
Higher SEER units, rated between 6 and 8, are now available in the UK market. This improvement has been driven by the 2026 Boiler Upgrade Scheme efficiency requirements, which push manufacturers to produce more efficient models (DESNZ Heat Pump Ready Programme data, 2026). If you are comparing heat pumps for cooling, always check the SEER rating on the product specification sheet, not the SCOP.
To run cooling, your heat pump must be a reversible model, not all are
Air-to-air heat pumps, often called heat-pump air conditioners, are inherently reversible and are the most common type used for cooling in the UK. Air-to-water heat pumps, which supply radiators or underfloor heating, may not include a reversing valve. You must check the manufacturer’s specification sheet to confirm whether the model is reversible (MCS installer guidance, 2026).
Ground-source heat pumps offer a different cooling option called passive cooling. In this mode, cool water from the ground loop is circulated directly through fan coils, without the compressor running. This uses very little electricity and can provide a significant cooling effect, but the system must be designed for it from the start (EST heat pump buyer’s guide, 2026). If you are buying a heat pump primarily for cooling, confirm with the installer that the model is reversible or that passive cooling is included.
Eligibility and certification verify your installer holds MCS and F-Gas certification for cooling
To qualify for the £7,500 Boiler Upgrade Scheme grant, your heat pump installation must be carried out by an MCS-certified installer. MCS stands for Microgeneration Certification Scheme, and it is a requirement for grant eligibility (GOV.UK Boiler Upgrade Scheme, 2026). For the cooling function, the installer must also hold F-Gas certification, which is mandatory for anyone handling refrigerants in reversible systems under UK regulations (Environment Agency F-Gas regulations, 2026).
Also, check that the installer is registered with TrustMark or a Competent Persons Scheme for the cooling element of the work. TrustMark is a government-endorsed quality scheme that covers both the heating and cooling aspects of a heat pump installation (TrustMark, 2026). Without these certifications, you risk invalidating your warranty and missing out on grant funding.
Cooling performance depends on outdoor temperature and house insulation
Heat pump cooling efficiency drops as outdoor temperatures rise above 30°C, because the temperature difference between the indoor and outdoor air increases. The system has to work harder to push heat out into hotter air, which reduces its SEER performance. DESNZ performance reports confirm that cooling output can fall by 10–15% when outdoor temperatures exceed 30°C (DESNZ heat pump performance report, 2026).
A well-insulated home with double glazing and loft insulation holds cool air for longer, reducing the system’s run time and electricity use. The Energy Saving Trust’s 2026 field trial data shows that homes with insulation upgrades cut cooling energy use by 20–30% (EST Heating and cooling in modern homes briefing, 2026). If your home is poorly insulated, the cooling cost will be at the higher end of the £150–£300 range, or potentially above it. heat pump running costs explained
The Boiler Upgrade Scheme in 2026 does not cover cooling, check if your grant applies
The £7,500 Boiler Upgrade Scheme grant, available in 2026, is specifically for heat pump installation for heating purposes. Cooling is considered an optional add-on, and the grant amount is not increased if the system includes a reversing valve (GOV.UK Boiler Upgrade Scheme guidance, 2026). You must confirm with your installer that the system is reversible and that the grant application is not contingent on the cooling capability.
Some local authority schemes or the ECO4 (Energy Company Obligation) programme may offer additional support for cooling if the home has vulnerable occupants, such as elderly residents or people with medical conditions that are worsened by heat. ECO4 eligibility is determined by the Department for Energy Security and Net Zero and is means-tested (DESNZ ECO4 eligibility, 2026). If you are relying on the Boiler Upgrade Scheme, budget for the cooling function as a separate cost. boiler upgrade scheme eligibility check
Frequently Asked Questions
Yes, a reversible heat pump can cool your home by reversing the refrigerant cycle. The Energy Saving Trust reports typical cooling costs of £150–£300 per season for a 3-bed semi (2026).
Running a heat pump for cooling costs £150–£300 per summer season, based on Ofgem's 2026 average rate of 27p per kWh. This covers 1,500–2,500 kWh of cooling energy for a 3-bed semi.
SEER stands for Seasonal Energy Efficiency Ratio; a typical SEER for UK heat pumps is 4–6, per MCS installer standards (2026). Higher SEER means lower electricity costs per cooling cycle.
Heat pumps generally use less electricity for cooling than for heating, as cooling requires less compressor work. The Energy Saving Trust notes summer cooling costs are typically lower than winter heating costs.
Yes, ground-source heat pumps can cool via a passive loop that bypasses the compressor, reducing electricity use. MCS data shows this can lower summer running costs compared to air-source systems.
