An Air Source Heat Pump (ASHP), also known as an Air to Water Heat Pump, works in a similar way to a Ground Source Heat Pump (GSHP). It differs in that it extracts heat out of the surrounding air instead of the ground. This might sound impossible during the winter months, but given that the refrigerant in a heat pump boils at around -30 degrees even the coldest weather feels hot to a heat pump!

ASHPs are compatible with both radiator based and under floor heating systems and can be used together with most electric boilers, oil-fired boilers or equivalent when docking to an existing heating/hot water system. All our ASHP systems are designed with an advanced controller that balances which systems are running when, distributes heating and/or hot water to the property and compensates for the weather throughout the year.

What are the advantages of an Air Source Heat Pump?

The main advantage of an Air Source Heat Pump is that you do not have the cost and disruption of laying the ground arrays. The main argument against ASHPs is that they are not quite as efficient as a GSHP. However, it can be argued that ASHPs are more efficient than GSHPs in the spring months as temperatures underground will usually have cooled to less than 6 degrees due to the effect of having freezing water running through the pipes throughout the winter months. The outdoor temperature, on the other hand, will be significantly higher allowing ASHPs to generate more energy. For pool owners, an ASHP is almost always the most economical option for pool heating. In the winter months you could expect an average COP (the ratio of heat produced vs the electricity required to run technology like heat pumps) of 3/1, and in the summer up to 5/1.

Not every ASHP is right for the UK climate.

Isoenergy understands this important fact that cheaper heat pumps, designed for much dryer winters and equipped with much smaller heat exchangers, freeze up in the UK's damp winter months. When this happens, the ASHP uses electricity to defrost the exchanger (a defrost cycle) whilst the property is forced to be heated by an electric back up or docked boiler. This decreases the efficiency of the system and costs the owner an unnecessary amount of money.

Isoenergy has rigorously tested all the ASHPs that we specify.

This testing ensures that the equipment we install has at least a large heat exchanger to maximise efficiency and minimise user costs. Furthermore, Isoenergy is not tethered to one manufacturer to ensure that we can continue to offer bespoke solutions rather than shoehorning one make or model into any given situation.

Is an Air Source Heat Pump right for me?

If you do not have enough room for a Ground Source Heat Pump (GSHP), want heating for a pool or need a smaller scale solution, an ASHP is generally ideal. To be certain, contact isoenergy on 01293 821345 or head to our contact page and we can advise you on whether an ASHP is the right solution.

Isoenergy has years of experience consulting on, designing and installing bespoke ASHP systems and can dock to existing systems or combine with other renewables such as Solar Thermal, Solar PV and Ground Source Heat Pumps.

An Air Source Heat Pump (ASHP) essentially works like a fridge in reverse.

Like a fridge, the ASHP runs on electricity. Unlike a fridge, the project's environmental advantages depend on the system's suitability for the UK climate and its Coefficient of Performance (COP - amount of heating and/or hot water produced by the system vs the amount of electricity needed to run the system).

1. The ASHP is filled with a refrigerant that boils at -30 degrees C. The system draws in the outside air and passes it over a heat exchanger, boiling the refrigerant instantly.
2. This low pressure gas is compressed, increasing the heat produced exponentially. The heat produced is transferred from the refrigerant to the heating and/or hot water system to be utilised in the property.
3. The condensed refrigerant is then circulated back to the cool side of the system to be evaporated by the outside air again.