Reduce your carbon footprint with an air source heat pump

An air source heat pump doesn’t produce carbon although it will use electricity. However, ASHPs can be combined with photovoltaic (PV) cells for a more environmentally friendly electricity source. 

 

Once installed, air source heat pumps have comparatively low running costs, especially when compared with off-grid energy such as liquified petroleum gas (LPG) or oil. They also work well with underfloor heating and low temperature radiators. 

 

There are grants available to offset the costs of installing an air source heat pump, such as the Renewable Heat Incentive (RHI), and replacement grants when this scheme ends in 2022. 

 

ASHPs might not be suitable for every home and to gain the full benefit your property will need to be well-insulated and airtight. You will still need an electricity supply to power your ASHP and your radiators or underfloor heating will need to be carefully sized. 

 

Overall, the efficiency of your air source heat pump system will depend on the difference between the air outside and your target indoor temperature for heating or hot water. Because an air source heat pump uses the surrounding air temperature it will be less efficient when the weather is cooler. However, they are used successfully in cold climates around the world. For this reason, it’s important to understand the heating requirements for your property in detail. 

 

An ASHP works very differently to a domestic boiler since it doesn’t create heat. Instead, heat is absorbed from the air into a fluid which then becomes a gas which can be moved using vapour compression, like a refrigerator. 

 

As well as running water-based central heating systems with radiators and underfloor heating, they can heat the air directly as an air conditioning system. 

 

You will need to consider more than replacing your boiler with an ASHP if you are planning a more traditional heating system with radiators rather than underfloor heating. 

 

A standard boiler operates at a high flow temperature of around 70°C, while an air source heat pump works at a lower temperature of around 35°C to 45°C for your radiator system and around 55°C for hot water. 

 

You will probably need to replace your existing radiators with ones that have a higher output, such as low-flow temperature radiators, oversized radiators, multi-finned aluminium radiators, or fan convectors. You will also want room temperature controls and compatible hot water storage. 

 

For new-build projects an air source heat pump is worth consideration as a reliable and long-lasting low carbon heating option for your home. The Renewable Heat Incentive could repay some of your costs even if you don't make big savings on your energy use compared to a traditional gas boiler.