Key Benefits

What is Air Source Heating?

Air source heat pumps extract low-grade heat from the air outside and use it to provide comfortable space heating and even everyday hot water.  They are at their most effective when used with underfloor heating systems, or radiators that operate at 50deg (e.g. oversized or aluminium)

While most systems are capable of providing at least 75% of space heating requirements, it is possible in many cases to provide up to 100% while also catering for hot water demands as well.  Naturally this is dependent on the level of insulation and type of heat distribution system in place.

How does it work?

Air source heat pumps work by converting the energy of the air outside into heat through the use of a compressor and heat exchanger.  This heat – in the form of water - is then available for distribution throughout your heating and hot water system. 

The efficiency of an air source heat pump is measure in Coefficient of Performance (CoP). A CoP of 4 means that for every kW of electricity you put in, you get 4kW of energy in the form of hot water by return.  When coupled, for example, to a low flow temperature system such as underfloor heating (35-45deg), the pump is able to provide far greater efficiency than a conventional boiler.  However, this efficiency does become somewhat less when the pump is paired with a standard radiator system due to the demand for higher flow temperatures. 

While some units are capable of proving temperatures in the region of 60-65deg, the CoP suffers as a result because the pump is having to work harder.   Therefore keeping the temperature at the lower end of the scale maximizes efficiency and longevity of the whole system.

The benefits

If your property has good levels of insulation and a low flow temperature heating system, then a correctly designed air source heat pump installation should cover all your heating requirements in all but the most extreme conditions.

In other words, the pump can actually be used as a replacement for a boiler, with an immersion being the preferred method of heating hot water when required.  Another alternative is to use solar thermal to provide your primary source of (free!) heating hot water during the summer, and as a supplement during winter.

This is worth noting if you are looking to replace your heating system – even more so if you are on oil or LPG - because the cost of an air source heat pump solution is likely to provide far greater payback and savings than a replacement boiler-fired system.

Is it suitable for my home?

Air source heat pumps are best-suited to properties with underfloor heating or over-sized/aluminium radiators.  If you have one of these systems in place already, or will be making alterations in line with this, for example, adding a large extension, then you should at least consider using air source.

Furthermore, if you are also running oil or LPG then you really should look at air source because the savings in terms of energy and money could be considerable.

How much does an Air Source Heat Pump cost, and what will I save?

Most standard 3-4 bedroom properties with the right heat distribution system would benefit from a £5000-£7000 air source installation.  For larger properties – especially those with lesser insulation or less efficient heating system – may require a larger pump or two or more of the same. 

In some scenarios it is possible for you to reduce your heating and hot water bills to zero, but it is more likely you will save in the region of 50-75%.

The important factor once again is to look at your future fuel costs.  Whatever you’re paying now is likely to double in 5 years and then double again in 10 years.  In other words, if you’re paying £1000 pa now, you can expect to be paying £2000 pa then £4000 pa respectively.  That’s a big price increase, even taking annual inflation into account.  With this in mind, you might like to look at air source as a viable means of protecting yourself from such increases and thus keep such figures in your pocket instead of the utility companies.