Jul 2022 Heat Pumps

From 2025, the UK Government is to ban boilers being installed in new build homes as part of their commitment to reducing emissions to zero by 2050. Though homes that already have gas boilers won’t have to get rid of them, the government is keen to encourage people to ditch gas in favour of using alternative fuels, as well as taking advantage of grants and incentives for insulating homes and installing low-carbon heating. Two of the options for this that are likely to be popular are air source heat pumps and ground source heat pumps.

In this article we’ll take a close look at both of them to help you decide should you be considering changing the way you heat your home or business.

What is an Air Source Heat Pump?

An air source heat pump absorbs heat from the outside air to heat your home and hot water. The heat is absorbed into a fluid , which passes through a compressor. This increases the temperature and transfers the higher temperature heat to the heating and hot water system within the house. Air source heat pumps can still extract heat when air temperatures are as low as -15 degrees C, but during winter they will require additional electricity to get the air up to the right temperature to provide heating and hot water.

Air source heat pumps are generally cheaper than ground source heating systems, as you only have to pay for the air source pump unit. However, air source heat pumps are less efficient than ground source systems, and will sometimes require extra electricity, meaning they could end up costing more in the long run. The upfront cost of an air source heat pump is usually between £6000 – £8000.

How is an Air Source Heat Pump Installed?

Air source heat pumps are fitted to the outside of your home, which means they are easier to install than ground source pumps as you don’t need to have your garden dug up. They look similar to air conditioning units and are connected to a unit inside the home that contains the hot water and circulation pumps. This internal unit is usually smaller than the average gas boiler, which frees up space in your house.

If there is an existing flue in your home, such as the one from your old boiler, an air source heat pump can be installed and running within a matter of days. In the UK you don’t need planning permission for an air source heat pump, as long as several limits and conditions are met.

How Long Does an Air Source Heat Pump Last?

Air source heat pumps have a relatively long life span and, properly looked after, they can last for up to 20 years. Servicing and maintenance should be done by a technician at least once a year, but there are several things you can do to ensure optimal performance, such as cleaning filters, checking for leaks, clearing dust and debris from your pump and checking refrigerant levels.

Most air source heat pumps have five-year warranties, meaning any teething problems can be ironed out without any extra cost.

What is a Ground Source Heat Pump?

Ground source heat pumps use a loop of pipes buried in the garden to extract heat from the ground. The pump circulates a mixture of water and antifreeze around the pipes and heat absorbed from the ground into the fluid is passed through a heat exchanger and into the heat pump. This heat is then used to heat your radiators and water. The cooled fluid then goes back into the loop where it requires further energy from the ground. The ground maintains temperatures of between 10-12 degrees C all year, which means the ground temperature in winter is always significantly warmer than the air temperature. This means that ground source heat pumps can produce a reliable level of heat all year without needing additional electricity.

The initial outlay for a ground source heat pump is typically between £14,000 – £19,000. However, whilst this might feel like an enormous sum, you will recoup the cost as they are very efficient when up and running. You will have lower heating bills and should be able to get money back from the energy you produce, for example through the UK government’s Renewable Heat Incentive (RHI) scheme and other incentives and grants being provided in England, Scotland and Wales. Having a ground source heat pump installed could potentially save around £1500 per year, meaning it would pay for itself within about a decade.

How is a Ground Source Heat Pump Installed?

The biggest barrier to having a ground source heat pump installed is whether you have a garden or not, as, if you have no outside space, a ground pump is not possible. You don’t need to have a particularly big garden, but it needs to be suitable for digging a trench or borehole and must be accessible to digging machinery. Having your garden dug up is inconvenient, so be prepared for that when deciding to have one installed. Once the ground work is completed installing the rest of the heat pump is no different to having a traditional boiler installed.

How Long Does a Ground Source Heat Pump Last?

A ground source heat pump should last up to 25 years, which is ten years longer than a gas boiler. However, the ground heat exchanger, which is the expensive part of having a heat pump installed, could have a lifespan of up to 100 years. The above ground part of the system should be checked every year by you, and a more detailed service should be done every three to five years by a professional installer.


Making the choice between having an air source heat pump or ground source heat pump is likely to come down to considerations of the amount of money you can afford on the initial outlay and the amount of space you have around your home. However, both are good options for saving money and helping to create a greener, cleaner future for everyone.

If you are thinking about a heat pump installation for your home or business and want to know more, then why not get in touch with the experts here at Invictus Mechanical.