Heat Pumps – low carbon heating systems

02 March 2023


Heat Pumps – low carbon heating systems

 What is a Heat Pump?

A heat pump is a low carbon heating system that can take warmth from the environment and use it to heat a building. Due to the environment being naturally heated by the sun, they are classed as renewable, despite the pump itself requiring electricity to run. Depending on your existing heating system, replacing it with a heat pump can help you to save money on your heating bill and produce fewer CO2 emissions. Planning permission is typically not required to install heat pumps.

There are two primary varieties of heat pump:

Ground source heat pumps (GSHP) involve networks of pipes being buried underground either in boreholes or trenches, which absorb the naturally stored warmth from the earth through the use of refrigerants and is compressed into usable heat within the property.

Air source heat pumps (ASHP) absorb the thermal energy that is present in the outdoor air. A fan  will bring the air into a unit, where it heats refrigerant and pumps it through a heat exchanger to create usable heat within the property.

Why are they becoming more popular?

As the UK strives to meet its climate commitments, heat pumps are becoming a vital and permanent fixture in the Building Regulations. They are low carbon and can provide a highly energy efficient source of heating when appropriately sized and paired with suitable interior heating elements. By 2025 it is quite likely that the upcoming Future Homes Standard will require traditional gas mains boilers to be phased out and replaced with heat pumps in new build dwellings. This is all part of the government’s strategy to achieve net zero carbon by 2050.

Currently there is a Boiler Upgrade Scheme (BUS) in place to provide upfront financial support to households upgrading their boilers to heat pumps. £450million has been made available for grants until 2025, and property owners can receive up to £6000 off the installation costs.


Is my property suitable for a heat pump?

Heat pumps are more effective in well insulated buildings, so a heat pump should not be your only tool to improve the energy efficiency of your home.

There are a few factors to take into consideration when thinking about upgrading to a heat pump. The first and most important is to decide which type of heat pump is the most suitable.

An ASHP can be installed faster and easier, due to not needing any ground excavation. A typical installation will involve what looks like an air conditioning unit mounted externally against an external wall of your property, possibly with a split system unit inside the building as well. They don’t require much space, but they can be noisy when the fan is running which can be disruptive to neighbours.

A GSHP requires a pipe network to be buried underground, and this can be in the form of 1 or more vertically dug boreholes or in horizontal trenches, which can require a large outdoor space to be available. A guideline for required outdoor space would be 2-3x the floor area of your property, accessible by road and clear of tree roots. The heat pump unit also has to be fitted internally. This entire installation process can be more expensive and more time consuming than with the ASHP.

Despite the differences in installation, both types of heat pump ultimately deliver the heat to your home in similar ways, so another consideration is what type of heating element to pair with the heat pump; radiators or under-floor heating? UFH can be quite disruptive to install but pairs well due to the higher efficiency of the low flow temperature of the heat pump, whereas radiators would need to be sized upwards to compensate for the lower temperatures. The design stage is highly important for an efficient heat pump system, and installation engineers can help with planning and sizing whichever system you decide on.