Air Source Heat Pump vs Ground Source Heat Pump: Which One Should You Choose?

When it comes to choosing an efficient and eco-friendly heating and cooling solution for your home, heat pump installation is on the rise in the UK. According to the Heat Pump Association, in 2021 the UK heat pump market nearly doubled, and there are plans to roll out 600,000 heat pumps every year until 2028. 

Among the various options available, two popular choices are the air-source heat pump and the ground-source heat pump. Both systems offer energy-efficient, sustainable and cost-effective ways to heat and cool homes and buildings, but there are significant differences. 

What is an air source heat pump? 

Air source heat pumps heat homes and buildings by absorbing heat from the outside air, which is then used to heat a refrigerant which turns into a vapour. The vapour is squeezed and compressed, and then released into your home, via your existing pipework, heating your home and water.

What is a ground source heat pump?

Ground source heat pumps (also known as ground-to-water heat pumps) transfer heat from the ground to heat radiators and other heat-emitting sources. 

Installation requirements 

Both air source heat pumps and ground source heat pumps should be installed by trained specialists, as this will help reduce any future problems that may occur.

Ground source heat pumps 

Ground source heat pumps require a considerable amount of outdoor space to fit a ground loop which can be installed vertically or horizontally. The ground also needs to be suitable for digging. If you don’t have much outdoor space, the pipes will need to sit vertically using boreholes, which increases installation costs. 

On average, you need 2.5 to 3 times more land than the floor area of the building. The land can’t be obstructed by tree roots and must be accessible via a digger.  Ground source heat pumps also require indoor space for the heat pump unit, which may or may not feature an integrated hot water cylinder. These units are usually the size of a large fridge freezer.

If your ground source heat pump is installed by a certified specialist, the pipework won’t be visible, and it won’t change the look of your property or the functionality of your outdoor space. 

Air source heat pumps 

Air source heat pumps still need outdoor space to be installed, but nowhere near as much. Air source heat pump units are often mounted outside the building they’re heating or cooling, which means they’re visible. 

Monobloc systems don’t have units inside the building, whereas split systems have a unit inside that’s usually the size of a traditional boiler. The size of your home or building will influence the size of the units needed. 

Placement of the unit must be considered as the fans generate noise, (between 450 to 60 decibels on average), especially in colder weather. After all, you don’t want to upset the neighbours! 

Installation costs 

Installation of air source heat pumps and ground-source heat pumps are vastly different, and this impacts the cost of having them installed. 

The average cost of installation of an air source heat pump is between £5,000 to £15,000, whereas ground source heat pumps start from £14,500 and £45,000. Factors such as boreholes and slinkies massively increase the cost of ground source heat pump installation.

Other common factors that may influence the cost of installing both types of heat pump include:

• The size and type of home or building 

• The types of heat emitters you have 

• Whether you need new insulation

The good news is that The Boiler Upgrade Scheme, also known as the Clean Heat Incentive, offers a £5,000 voucher off the price of installing renewable heating solutions, to help with the cost of heating their homes. You can receive £5,000 and £6,000 vouchers for biomass boilers and ground source heat pumps respectively.

Efficiency and environmental impact

Thanks to advancements in technology, air source heat pumps and ground source heat pumps are now levelling up in efficiency. Previously, ground source heat pumps were known for being slightly more efficient than air source heat pumps, but the gap is closing! 

Air source heat pump technology has evolved to perform well even in colder climates, making them a viable choice for regions that experience harsh winters. Air source heat pumps are 400% more efficient compared to new gas boilers which are only 90% efficient. For every kW of electricity you put in an MCS-approved heat pump, you get 4kW of energy out.

Additionally, the installation footprint of an air source heat pump is far less. This is because ground source heat pumps require much more energy in the excavation process, which also disrupts the landscape and requires significant energy for drilling and installation of ground loops. Whereas air source heat pumps have a simpler installation process that generates fewer disturbances to the environment.

Maintenance and upkeep

Air source heat pumps generally have lower maintenance requirements compared to ground source heat pumps as they don’t need as much maintenance on the ground loops, which can be a significant advantage in the long run. The ground loops of GSHPs can sometimes be susceptible to issues like leaks or blockages, which could result in costly repairs.

Get in touch with Enula today to see how we can help you make the switch toward air source heat pumps.