Air Source Pumps

What is an Air Source Heat Pump (ASHP)?

If the adjacent photograph looks similar to a device you have outside your home, then you have an Air Source Heat Pump.

The ASHP converts energy which it absorbs from outside into usable heat for the home, where it can be used to heat radiators and hot water. Heat is provided through radiators in a similar manner to a traditional gas central heating system.

How should I use the system?

Although your home has radiators, a room thermostat and thermostatic radiator valves (TRVs), just like a traditional gas heating system does, it is important that you understand how to control this system in the most efficient manner – using the system inefficiently may incur unnecessary expense (higher electricity bills) and could reduce your levels of thermal comfort:

  • Set the room thermostat at an appropriate temperature, usually around 19 – 21°C
  • Alter the thermostat by only a few degrees at a time, e.g. if you are feeling a little warm, turn the thermostat down by a couple of degrees only. Do not turn it down to say 10°C; whilst this will lower the temperature of your home it will, in effect, turn the ASHP off, then if you start to feel cold it will take the ASHP a considerable amount of time and electricity to heat your home again.
  • If you are not at home during the day, e.g. you are at work, it is more efficient to keep the heating on at a reduced temperature rather than switch it off completely.

One important fact to remember is that it will take the ASHP longer to heat your home than a traditional gas system, therefore turning your heating on and off regularly is not only inefficient (it will increase your electricity bills) but you may feel cold for longer whilst waiting for your home to heat up.

The recommended method for controlling your ASHP is to leave the heating on almost constantly and control the temperature using the room thermostat. During installation, our contractor will set the hot water and heating times to reflect these recommendations.

What electricity tariff should I be on?

It is vitally important that you are on the correct tariff. It is up to you to determine what the most suitable tariff is, we cannot tell you.

However, our recommendation is that you should be on a flat rate tariff and not economy 7. Whilst a flat rate tariff is our recommendation a small number of users have reported success with the economy 10 tariff. Your circumstances will determine which tariff is best for you

Remember to shop around regularly (at least once a year) to get the best tariff.

We recommend that you provide your electricity supplier with regular meter readings to ensure you are not over or underpaying on your bill. Doing this during the first year after installation of the ASHP may help you understand the running costs associated with your new heating system.

Will the ASHP save me money in comparison with other heating systems?

There is no straightforward answer to this question. It depends on many variables, for example, what type of heating system you had previously, how often you used it, what electricity tariff you were on, how well insulated your home is and how efficiently you use the ASHP.

But as mentioned earlier, in order to get the most out of your ASHP, you must be on the correct electricity tariff and ensure you use the ASHP efficiently (see ‘how should I use the system’).

How do I use the controls?

Room thermostat

  • This device is adjusted by the user to set the desired temperature within the property.
  • The up and down arrows to the right-hand side allow you to adjust the temperature of your home – press the up arrow to increase the temperature, and the down arrow to decrease it.
  • The top left button (which looks like a tap); pressing this will boost the hot water for an hour, should you need to do so.
  • To the bottom left you will find the ‘Holiday button’. Using this option will allow you to set the heating to come on after a specific period of time – up to a maximum of 72 hours.
  • The batteries in your wireless room thermostat will be changed at each service, however, if they require changing before the service is due then please contact our customer services team using the link at the bottom of this page.


The programmer is a complex device. It allows a qualified engineer to make alterations to integral settings within the ASHP as well as changes to other settings, such as times of when the hot water or heating come on.

Our recommendation is that you do not touch this device unless you are particularly competent in using electronic devices and their associated software.

Please be aware, altering settings incorrectly on this device can change critical settings within the ASHP.

If you are at all uncertain, either contact customer services for assistance or wait for the annual service when an engineer will visit.

Finally, under no circumstances must radiators be removed, drained down or bled. Please contact us should you require any of these services.