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Air Source Heat Pumps

Heat your home with energy absorbed from the air around you.

Air source heat pumps absorb heat from the outside air. This heat can then be used to heat radiators, underfloor heating systems, or warm air convectors and hot water in your home.

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can get heat from the air even when the temperature is as low as -15° C. Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally.

 

How do air source heat pumps work?

Heat from the air is absorbed at low temperature into a fluid. This fluid then passes through a compressor where its temperature is increased, and transfers its higher temperature heat to the heating and hot water circuits of the house. There are two main types of air source heat pump system:

  • An air-to-water system distributes heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. So they are more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.
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  • An air-to-air system produces warm air which is circulated by fans to heat your home. They are unlikely to provide you with hot water as well.

 

The benefits of air source heat pumps

Air source heat pumps (also known as ASHPs):

  • could lower your fuel bills, especially if you are replacing conventional electric heating
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  • could provide you with an income through the government’s renewable heat incentive (RHI)
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  • could lower your home’s carbon emissions, depending on which fuel you are replacing
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  • don't need fuel deliveries
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  • can heat your home and provide and hot water
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  • need little maintenance

Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. During the winter they may need to be on constantly to heat your home efficiently. You will also notice that radiators won't feel as hot to the touch as they might do when you are using a gas or oil boiler.

 

Savings

How much you can save will depend on what system you use now, as well as what you are replacing it with. Your savings will be affected by:

  • Your heat distribution system
    If you have the opportunity, underfloor heating can be more efficient than radiators because the water doesn’t need to be so hot. If underfloor heating isn’t possible, use the largest radiators you can. AFS can advise you on this.
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  • Your fuel costs
    You will still have to pay fuel bills with a heat pump because it is powered by electricity, but you will save on the fuel you are replacing.  If the fuel you are replacing is expensive you are more likely to make a saving.
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  • Your old heating system
    If your old heating system was inefficient, you are more likely to see lower running costs with a new heat pump.
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  • Water heating
    If the heat pump is providing hot water then this could limit the overall efficiency.  You might want to consider solar water heating to provide hot water in the summer and help keep your heat pump efficiency up.
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  • Using the controls
    Learn how to control the system so you can get the most out of it. You will probably need to set the heating to come on for longer hours, but you might be able to set the thermostat lower and still feel comfortable. Your installer should explain to you how to control the system so you can use it most effectively.