Can a Heat Pump Cool Your House? Air-to-Air, Fan Coils and Underfloor Cooling Explained
Last reviewed: 14 July 2026
Yes, some heat pumps can cool a house, but cooling is not an automatic feature of every heat-pump installation. An air-to-air heat pump can normally provide both heating and cooling through indoor fan units. An air-to-water heat pump may also provide cooling, but only if the heat pump, controls, pipework and heat emitters have been designed for it.
The quick answer: air-to-air heat pumps are generally the simplest option for combined heating and cooling. An air-to-water system needs a reversible heat pump and suitable emitters such as cooling-rated fan coils or a properly designed radiant-cooling system. Ordinary panel radiators should not be assumed suitable.
There is a big difference between a heat pump that is technically capable of reversing its refrigeration cycle and a complete heating system that can safely distribute cooling around a home. Condensation, insulation, condensate drainage, humidity control and emitter performance all need to be considered.
Before installing active cooling, it is also worth reducing the heat entering the property. External shading, sensible ventilation, closing blinds before rooms overheat and improving solar control can reduce the cooling load considerably.
How does a heat pump cool a house?
A heat pump normally moves heat from a lower-temperature source to a higher-temperature destination. In heating mode, an air source heat pump collects energy from the outdoor air and transfers it into the home.
A reversible heat pump can change the direction of this process. In cooling mode, it removes heat from inside the property and rejects it outdoors.
What happens next depends on the type of system:
- Air-to-air heat pump: refrigerant travels between an outdoor unit and one or more indoor units. The indoor units blow cooled air directly into the rooms.
- Air-to-water heat pump: the heat pump cools water that must then circulate through suitable fan coils, radiant surfaces or another cooling-rated distribution system.
Not every heat pump is reversible, and not every controller has cooling enabled. Always check the exact model, installation manual and system design rather than assuming that a menu setting can turn a heating-only installation into air conditioning.
Air-to-air heat pumps: usually the simplest cooling option
An air-to-air heat pump works much like the reversible air-conditioning systems seen in hotels, offices and homes in warmer countries. An outdoor unit is connected by refrigerant pipework to one or more indoor units.
During winter, the indoor unit supplies warm air. During summer, the refrigeration cycle reverses and the same indoor unit supplies cooled air.
Advantages of air-to-air cooling
- It can heat and cool using the same equipment.
- Rooms can cool relatively quickly because air is moved directly across a cooling coil.
- Individual indoor units can provide room-by-room temperature control.
- Cooling normally removes some moisture from the indoor air as condensate forms on the cooling coil.
- It does not require radiators or wet underfloor heating.
- It can suit flats, smaller homes, park homes and properties without an existing wet central-heating system.
Disadvantages to consider
- Indoor units must be positioned where air can circulate properly.
- Wall-mounted, floor-mounted or ceiling units remain visible inside the property.
- Each cooling unit needs a correctly designed condensate drain.
- Multiple rooms may require several indoor units and additional pipework.
- The indoor units contain fans, so they produce some noise and air movement.
- Most air-to-air systems do not provide hot water for taps, baths or showers.
An air-to-air unit also recirculates the air already in the room. It should not be confused with a ventilation system supplying fresh outdoor air. The home still needs appropriate ventilation.
For smaller properties, read my related guide on where a heat pump can be installed in a flat.
Can an air-to-water heat pump provide cooling?
Some air-to-water heat pumps can provide active cooling by producing cool water instead of warm water. However, the whole system must be designed around cooling operation.
A suitable installation may need:
- A reversible heat pump approved for cooling operation.
- Controls that can change correctly between heating and cooling.
- Cooling-rated fan coils or a purpose-designed radiant system.
- Dew-point or humidity monitoring.
- Insulation around every pipe, valve and fitting carrying cool water.
- Condensate trays, traps and drains where water may form.
- Controls that prevent heating and cooling zones fighting one another.
- A clear control strategy for domestic hot-water production.
This is why it is misleading to describe cooling as a free extra that can simply be switched on after an ordinary heat-pump installation has been completed.
Why fan-coil units work better than ordinary radiators
A fan-coil unit contains a water coil and a fan. Cool water passes through the coil while the fan draws room air across it and returns cooled air to the space.
Cooling-rated fan coils may be wall mounted, floor mounted, concealed in a ceiling or connected to short sections of ductwork. Because air is forced across the coil, they can transfer considerably more cooling than an ordinary panel radiator of a similar size.
A proper cooling fan coil may also include:
- A condensate collection tray.
- A drain connection or condensate pump.
- Insulated water connections.
- Fan-speed control.
- An air filter.
- Cooling-output data at specified water and room temperatures.
Do not assume that every fan convector is suitable. Some products are designed only for heating and have no condensate management or certified cooling-output information.
Can standard radiators be used for cooling?
Standard domestic panel radiators are generally a poor choice for cooling and should not be connected to chilled water without a system-specific design.
There are several reasons:
- Condensation: if the radiator surface falls below the room’s dew-point temperature, moisture can form on the radiator, valves and pipework.
- No condensate drain: ordinary radiators are not fitted with trays or drainage connections.
- Limited natural convection: radiators are arranged to warm air that then rises. In cooling mode, cold air falls, so the normal airflow pattern is less effective.
- Uninsulated fittings: valves, tails and nearby pipes may become wet even if the main radiator surface appears dry.
- Risk to finishes: repeated moisture can affect flooring, skirting boards, decorating and nearby furniture.
There are specialist emitters that resemble radiators but contain fans and are specifically rated for cooling. These should be treated as fan coils rather than as ordinary radiators.
Can underfloor heating pipes cool a house?
Water-based underfloor pipework can sometimes be used for radiant cooling, but it must be designed and controlled for that purpose. Simply circulating very cold water through an existing underfloor-heating manifold is not a safe shortcut.
Underfloor cooling works by keeping the floor slightly cooler than the room. Heat then transfers from the room and its occupants into the floor.
The main limitations of underfloor cooling
- The cooling output is usually lower than the heating output of the same floor.
- The floor surface must remain above the room’s dew-point temperature.
- Humidity can change during the day, so a fixed water-temperature setting is not enough.
- Floor coverings affect performance.
- Rugs, furniture and thick carpets reduce the active cooling area.
- Bathrooms, kitchens and rooms with high moisture loads need particular care.
- Radiant cooling does not remove moisture from the air in the same way as a cooling coil operating below dew point.
A suitable control system normally monitors temperature and humidity and raises the water temperature, reduces cooling or shuts the circuit down when condensation becomes possible.
Underfloor cooling may provide useful background cooling in a well-insulated home with a modest summer heat load. It is less likely to deal with a heavily glazed room that overheats rapidly in direct sun.
For more information on the heating side of these systems, see my guide to underfloor heating and low flow temperatures.
What is dew point, and why does it matter?
Dew point is the temperature at which water vapour in the air starts condensing on a cooler surface.
You can see the same effect when moisture appears on a cold drinks can. In a cooling system, that moisture could appear on:
- Pipes.
- Valves.
- Manifolds.
- Radiators.
- Floor surfaces.
- Fan-coil casings.
- Ceilings or walls around concealed pipework.
Dew point is not fixed. It changes with room temperature and humidity. A water temperature that causes no problem on a dry afternoon may cause condensation when humidity rises after cooking, showering or opening windows during muggy weather.
A properly designed system therefore needs more than a low-temperature thermostat. It may require humidity sensors, dew-point calculation, mixing controls and automatic protection.
Why chilled-water pipe insulation is essential
Heating pipes are often insulated mainly to reduce heat loss. Cooling pipework needs vapour-resistant insulation to prevent warm, humid room air reaching the cold pipe surface.
Every part of the cool-water circuit may need attention, including:
- Straight pipe runs.
- Elbows and tees.
- Pump bodies.
- Valves.
- Strainers.
- Manifolds.
- Flexible hoses.
- Connections inside fan-coil units.
Small gaps in the insulation can become local condensation points. Concealed leaks of condensate can remain unnoticed until staining, corrosion or damage appears.
What happens to your hot water while the heat pump is cooling?
Most air-to-air heat pumps do not normally produce domestic hot water, so another appliance or cylinder arrangement is needed.
An air-to-water heat pump may be able to cool rooms and heat a domestic hot-water cylinder, but it will not necessarily do both simultaneously. Many systems temporarily pause space cooling while heating the cylinder.
The exact behaviour depends on the heat pump, valves, cylinder, controls and hydraulic design. Ask the designer to explain:
- How often cooling will stop for hot-water production.
- How long a normal hot-water cycle is expected to take.
- What happens during high cooling and hot-water demand.
- Whether any direct-electric backup is used.
- How the system changes safely between modes.
Does heat-pump cooling use a lot of electricity?
Active cooling uses electricity because the compressor, pumps and fans must run. There is no single running-cost figure that applies to every home.
The cost depends on:
- The cooling load of the property.
- Outdoor temperature and humidity.
- The indoor temperature selected.
- The efficiency of the heat pump in cooling mode.
- The number of rooms being cooled.
- How well the property is shaded and insulated.
- Fan, pump and control consumption.
- Your electricity tariff.
A simple estimate is:
Electrical input in kW × hours of operation × electricity price per kWh = estimated running cost.
Use measured electrical input or reliable design data rather than the heating or cooling output shown on the front of a brochure. A system delivering several kilowatts of cooling should not necessarily be drawing the same number of kilowatts from the electricity supply.
Related reading: how much heat pumps cost to run.
Try to reduce overheating before adding mechanical cooling
Cooling equipment works best when it is not fighting avoidable solar and internal heat gains.
Useful measures can include:
- Use external blinds, awnings or shutters where appropriate.
- Close internal blinds or curtains before direct sunlight enters the room.
- Ventilate when outdoor air is cooler than the air inside.
- Reduce unnecessary heat from lighting and electrical equipment.
- Check loft insulation and uncontrolled air leakage.
- Consider solar-control glazing or film where technically and visually appropriate.
- Use zoning so empty rooms are not cooled unnecessarily.
Be careful with overnight window opening where security, noise, pollution or fire-safety considerations make it unsuitable.
Planning permission for a heat pump that provides cooling
Planning rules vary across England, Scotland, Wales and Northern Ireland.
In England, an air source heat pump may qualify as permitted development when all the relevant conditions are met. Current conditions include limits relating to equipment size, number of outdoor units, location, noise and designated land. A unit relying on these rights must not be used solely for cooling.
Permitted development rights can also be restricted by listed-building status, planning conditions or an Article 4 Direction. Flats, leasehold properties and shared buildings may require separate freeholder or leaseholder consent even where planning permission is not required.
Check the current rules with the relevant planning authority before work begins.
Are grants available for air-to-air heat pumps?
As of 14 July 2026, the Boiler Upgrade Scheme lists a grant of £2,500 towards an eligible air-to-air heat pump in England and Wales.
Eligibility conditions apply, the scheme is installer-led and funding rules can change. Check the current GOV.UK and Ofgem guidance before relying on the grant in a quotation or project budget.
Is heat-pump cooling a DIY job?
Choosing shading, using blinds and operating existing controls are reasonable homeowner tasks. Designing or modifying a refrigeration or chilled-water system is not.
Professional work may include:
- Opening or altering a refrigerant circuit.
- Selecting and positioning indoor and outdoor units.
- Calculating room heating and cooling loads.
- Designing condensate drainage.
- Installing fixed electrical supplies.
- Selecting cooling-rated fan coils.
- Applying vapour-resistant insulation.
- Configuring dew-point and humidity protection.
- Commissioning flow rates, controls and safety functions.
Refrigerant work must be completed by appropriately qualified personnel. Electrical, drainage and building work must also comply with the applicable requirements and manufacturer instructions.
Which heat-pump cooling system is likely to suit your home?
Consider air-to-air when:
- You want direct heating and cooling.
- The property is a flat or smaller home.
- There is no wet central-heating system.
- You are comfortable with visible indoor units.
- You have another suitable way to produce domestic hot water.
Consider air-to-water with fan coils when:
- You want heating, hot water and cooling considered as one designed system.
- The heat pump is approved for reversible operation.
- There is space for cooling-rated fan coils and condensate drains.
- The pipework can be insulated properly.
- The controls can provide reliable humidity and dew-point protection.
Consider radiant underfloor cooling when:
- The property has a relatively low and predictable cooling load.
- The floor construction and coverings are suitable.
- The system includes humidity and dew-point controls.
- You understand that cooling output may be limited.
- Another system can deal with humidity or peak cooling loads where necessary.
Questions to ask an installer
- Is the exact heat-pump model approved for cooling?
- What is the calculated cooling load for each room?
- Which emitters will provide the cooling, and where is their performance data?
- How will condensation be prevented?
- Where will condensate water drain?
- Which pipes, valves and pumps will receive vapour-resistant insulation?
- How will humidity and dew point be monitored?
- What happens when domestic hot water is required?
- What noise should be expected indoors and outdoors?
- What is the estimated electrical consumption under the proposed design conditions?
- Does the installation need planning, freeholder or building-control approval?
- Who will commission and maintain the system?
Frequently asked questions
Do all air source heat pumps provide cooling?
No. The heat pump must support reversible operation, and the rest of the installation must also be designed for cooling.
Is an air-to-air heat pump the same as air conditioning?
A reversible air-to-air heat pump is essentially a system that can provide air conditioning in summer and space heating in winter.
Can I turn my radiators cold to cool the house?
Ordinary radiators should not be used in this way without a specialist design. Condensation, limited output and the absence of drainage are significant problems.
Can underfloor heating cool a room?
Water-based underfloor pipework can provide radiant cooling when it has been designed for cooling and protected by suitable humidity and dew-point controls.
Will an air-to-air heat pump heat my tap water?
Most air-to-air systems do not normally provide domestic hot water. A separate hot-water solution is usually required.
Does a cooling heat pump bring fresh air into the house?
Most room air-to-air systems recirculate indoor air. They do not replace the need for suitable ventilation.
Can I add cooling to an existing heat-pump system?
Possibly, but the heat pump model, controls, emitters, insulation, valves and drainage must all be assessed. Enabling a setting without checking the complete installation can cause condensation and poor performance.
The bottom line
A heat pump can cool a house, but the right method depends on the type of heat pump and the way cooling is distributed.
Air-to-air systems provide the most direct route to combined heating and cooling. Reversible air-to-water heat pumps can also work, particularly with properly selected fan coils, but they require more attention to pipe insulation, controls and condensate drainage. Underfloor cooling is possible, although its output and condensation limits must be understood.
The important point is to design the complete system for cooling from the start. A reversible heat pump on its own does not make ordinary radiators, uninsulated pipework or a heating-only underfloor system suitable for chilled water.
For more background, read how a heat pump works and my guide to air source heat-pump installation.