Air Source Heat Pumps

Even cold outside air contains thermal energy. The heat pump absorbs this energy and uses a refrigerant and compressor to raise its temperature before transferring the heat into your home.

Yes. Air source heat pumps are designed to operate in cold outdoor temperatures. Their performance can change as temperatures fall, which is why correct system sizing and design are important.

During cold and damp weather, some frost or ice can naturally form on the outdoor unit. The heat pump will automatically run a defrost cycle, temporarily warming the outdoor coil to remove the ice before returning to normal heating operation.

This is a normal part of how an air source heat pump operates in colder conditions.

Air source heat pumps contain a fan and compressor, so they do produce some sound when operating. Modern units are designed with noise in mind, and careful positioning and system selection can help minimise its impact.

Not exactly. A boiler creates high-temperature heat by burning fuel, whereas a heat pump moves heat from the outside air into your home and generally operates more efficiently using lower heating temperatures over longer periods.

Yes, when the system is correctly designed. Heat pumps often provide a steadier, more consistent level of heating rather than the shorter bursts of high-temperature heat people may be used to from a boiler.

They can operate for longer periods at lower temperatures, particularly during colder weather. This isn't necessarily a problem — heat pumps are designed to maintain a comfortable temperature efficiently rather than repeatedly heating the home from cold.

Possibly. Because heat pumps generally operate at lower flow temperatures than traditional boilers, some existing radiators may need to be increased in size or replaced to provide enough heat to individual rooms.

No. Air source heat pumps can work with radiators, underfloor heating or a combination of both. The important factor is whether the heating system can provide enough heat at the temperatures the heat pump is designed to operate at.

A larger radiator has more surface area, allowing it to transfer enough heat into the room while using the lower water temperatures commonly associated with efficient heat pump operation.

Good insulation can significantly improve heat pump performance by reducing the amount of heat your home loses. The property's insulation and heat loss should therefore be considered when designing the system.

A heat loss calculation estimates how much heat each room and the property as a whole loses through walls, windows, floors, roofs and ventilation.

This helps determine the correct heat pump size and heating requirements for the property.

The system should be based on the property's calculated heat loss and hot-water requirements, rather than simply choosing a heat pump based on floor area or the size of the existing boiler.

COP (Coefficient of Performance) describes how much heat a heat pump produces compared with the electricity it uses.

For example, a COP of 4 means that under those particular operating conditions, 1 kWh of electricity produces around 4 kWh of heat.

SCOP (Seasonal Coefficient of Performance) looks at heat pump efficiency across a whole heating season, rather than at one particular operating condition. It can therefore provide a more useful indication of expected seasonal performance.

Potentially, but this depends on your existing heating system, electricity tariff, property efficiency, system design and how the heat pump is operated. A properly designed and controlled system is important for achieving good performance.

Yes. A suitable air source heat pump system can provide both space heating and domestic hot water, usually using a hot-water cylinder to store heated water for showers, baths and taps.

Usually, if the heat pump is providing your domestic hot water. Unlike many combi boilers, a typical heat pump system uses a hot-water cylinder to store hot water ready for use.

The outdoor unit requires a suitable location with adequate airflow and appropriate clearances. Positioning also needs to consider access, pipework, appearance and potential noise impact.

Yes. Heat pump systems use heating controls to manage temperatures and operation. However, they are often most efficient when maintaining a steady temperature rather than being repeatedly switched on and off like a traditional boiler.

Weather compensation automatically adjusts the temperature of the water going around your heating system based on the outside temperature.

When it's milder outside, the heat pump can use a lower temperature; when it's colder, it can increase it. This can help improve comfort and efficiency.

Yes. Solar PV can generate electricity that may help supply the electricity used by your heat pump when solar generation and heat-pump operation occur at the same time.