air source heat pump

Is an Air Source Heat Pump right for me?

Air source heat pumps are increasing in popularity all the time, but to tell if they are suitable for your home, there are a few key things to consider.

Do you have somewhere to put it?

You need a space outside your home where the heat pump can be installed placed on the ground. The unit needs sufficient room around it to get a good flow of air. A sunny spot is ideal.

Do you have space inside the house?

You will need to fit / replace a hot water cylinder if you want to use the heat pump to provide domestic hot water as well as space heating. Cylinders for heat pumps tend to be a bit larger than for normal heating systems as you will store the water at slightly lower temperatures, therefore you need to store more of it. Air source systems also need a buffer tank but the Dimplex system cleverly fits this into the hot water cylinder, so no extra floor space is required!

Is your home well insulated?

Since air source heat pumps work best when producing heat at a lower temperature than traditional boilers, it is essential that your home is well insulated and draught-proofed for the heating system to work efficiently. To qualify for the Renewable Heat Incentive, you require 250mm of loft insulation and (where appropriate) cavity wall insulation.

What fuel will you be replacing?

The system will pay for itself much more quickly if it's replacing solid fuel, oil, lpg or electric heating. Heat pumps may not be the best option for homes that use mains gas, as although it can reduce running costs, the savings that can be made at current gas prices mean it will take some time to recover the installation costs.

What type of heating system will you use?

Air source heat pumps can perform better with low temperature heating systems, such as underfloor heating or low temperature, fan assisted radiators – such as Dimplex SmartRads. Heating with normal radiators is possible, but the overall efficiency of the system will be affected because the heat pump will have to heat the water to a higher temperature.

Is the system suitable for a new development?

Air source heat pumps can be used in existing homes, refurbishments or new homes. New properties have the benefit of good insulation and so are ideal for heat pumps. Combining heat pump installation with renovation work can reduce the overall cost of installing the system in an existing property.

Will I need planning permission?

This varies depending on you location in the country, in Wales and Northern Ireland air source heat pump installations require planning permission, however in England and Scotland they may be considered Permitted Development, in which case you will not need planning permission, but the criteria are complex so it is always a good idea to check with your local planning office.


As of the 1st December 2011, domestic air source heat pump systems are classed as Permitted Development provided that they comply with certain criteria, including:

  • There is no wind turbine at the property.
  • The external unit is less than 0.6 m3 in size.
  • It is more than one metre from the edge of the householder's property.
  • It is not on a pitched roof, or near the edge of a flat roof.
  • It meets additional criteria if in a conservation area, World Heritage Site etc.

This list is not comprehensive, please contact your local planning office for full details.


A domestic installation of an air source heat pump in Scotland is currently permitted unless:

It would result in the presence within the curtilage of a dwelling of more than one air source heat pump.

The air source heat pump would be situated less than 100 metres from the cartilage of another dwelling.

The air source heat pump is visible from the road in a conservation area.

The air source heat pump would be within a World Heritage Site or the curtilage of a listed building.

How much could I save?


Running costs will vary depending on a number of factors - including the size of your home, how well insulated it is and the type of heating system it will be connected to. Use our savings calculator to get an approximate idea of the savings you could make by installing a heat pump. Your savings will be affected by:

Your heat distribution system

If you are replacing or specifying the heat distribution system, low temperature radiators – such as Dimplex SmartRads or underfloor heating will be more efficient than radiators because the water temperature can be lower. Underfloor heating is not always an option in existing homes, but SmartRads can be easily wall mounted to replace existing radiators. Alternatively, use the largest radiators you can, but this will be less efficient. Ask your installer for your best option.

Your fuel costs

You will still have to pay fuel bills with a heat pump because they are powered by electricity, but you will save on the fuel you are replacing. If the fuel you are replacing is expensive – such as oil, lpg or solid fuel you should make a significant saving.

Your heating system

If your existing heating system is inefficient, you are more likely to see lower running costs with a new heat pump.

Water heating

If the heat pump is to provide domestic hot water this may impact on the overall efficiency as the heat pump achieves its best efficiency when working at low temperatures. However, depending on your current fuel there are still likely to be savings if the system is designed and installed properly.

Using the controls

Learn how the system controls work so you operate it at maximum efficiency. Generally heat pumps are designed to work at lower water temperatures, so the characteristics will be different to a conventional boiler system. You may need to set the heating to come on for longer hours, but should be able to set the thermostat at a lower temperature and achieve the same level of comfort. Your Dimplex Renewables installer will explain to you how to control the system so you can use it most effectively.


Installing a typical system costs around £6,000 to £10,000, depending on the size of the property and heating demand, but the average payback is usually 4-5 years.