As fuel bills continue to rise, and utility companies seem to forever tighten their grip on consumers, the search for alternative energy sources grows increasingly desperate for alternative solutions. One of the solutions that’s growing in popularity for heating are Air Source Heat Pumps (ASHPs), so here’s a quick guide to them.

When an air source

Although ground source heat pumps are available, it could be the case that there is not suitable land area, or perhaps you have a highly insulated new build property. In both cases, an air source heat pump could prove a viable alternative.

ASHPs are compatible with most electric boilers, oil-fired boilers or equivalent heat pump could be of use

, and can be relatively easily docked to an exiting heating/hot water system.

What an air source heat pump can do for you

An air source heat pumps works by extracting energy from the outside air – similar to a fridge does to extract heat from its inside – which is then drawn across an evaporator heat exchanger by a fan.

ASHPs function year-round, even in the winter, and are available in two main systems :-

  • air-to-water (heat via wet central heating system)
  • air-to-air (circulated by dieting fans, and often restricted to spatial heating and cooling only).

An ASHP is preferable to a ground-based system as it does not the underground arrays nor a water source.

Generally, air source heat pumps often prove to be very economically efficient, especially for items such as swimming pools, and can also be docked with renewables such as Solar PV and Solar Thermal systems.

What to think about before installing an air source heat pump

Above anything, it’s vital you work with an established and experienced provider of air source heat pumps such as Isoenergy who can advise, design and install a complete system for you.


Preferably, the ASHP should be located as close to the utility/plant room as possible, with good air flow to input and exhaust sides, and not underneath anywhere likely to deposit falling debris such as leaves from trees.

Clearances MUST be observed, otherwise there will be low air flow, which will result in the cold exhaust air being recycled into the system.

Civil works/building work

A solid base with condensate soaraway is required to seat a air source heat pump.

Single or three phase electricity?

Power source (three phase or single phase?) is important, as this will need to run to the proposed location of the ASHP.

Heating emitters or distribution system

Because of lower water temperatures required, air source heat pumps generally perform better with underfloor heating, or warm floor heating, than with radiator-based systems. This does not mean they won’t work with radiation-based systems, just that consideration to this should be given at design stage.