Ground Source Heat Pump Costs 2021

Fossil fuel-guzzling boilers are finally being phased out, leaving room for alternative home-heating methods. One such method is a ground source heat pump, which has increased in popularity and looks set to become one of the leading technologies in our fight against climate change.

Unlike gas-powered boilers, ground source heat pumps require no fossil fuels to function, making them an excellent choice for people keen to heat their homes sustainably. How much do they cost though? And what about running costs? We’re answering all that and more here.

3D visualisation of a ground source heat pump

What is a ground source heat pump?

 

Unlike traditional boilers, ground source heat pumps don’t use fuel. Instead, a ground source heat pump runs water (often mixed with antifreeze) through pipes underground, which is then heated by your garden soil’s ambient warmth, or if using a borehole, the heat stored further underground.

The water is then run through a heat exchanger in your home, compressing it to generate heat. Once compressed by the heat exchanger, the heat extracted is then transferred to your home’s heating system.

 

Horizontal vs. vertical ground source heat pumps

 

There are two types of ground source heat pumps — horizontal and vertical.

Horizontal is where the groundwork and piping required is spread across a wider area in your garden, or wherever the heat pump will be installed. The space required for a horizontal installation means rural properties with large gardens are often far better suited. Typically, a minimum of 700 square metres is needed for the underground piping (known as ground loops).

Vertical ground source heat pumps require a deep borehole to be drilled, which is better for properties with smaller gardens. This requires heavy specialist machinery to dig the hole, which adds a lot to the overall cost. The boreholes are typically 100m deep, so no, your garden won’t look like 2003’s core-drilling epic, The Core.

How much does a ground source heat pump cost?

 

Compared to traditional gas-powered boilers, the upfront costs for ground source heat pumps is much higher. They start from around £13,000, going all the way up to £35,000 for more complex installations (typically vertical installations). There’s the unit itself, the required groundwork (either a trench system or borehole), and the installation itself.

Despite these high costs, the UK government’s Renewable Heat Incentive (RHI) will help cover some of the initial outlay and reduce the running costs of your ground source heat pump. It’s important to note that the Renewable Heat Incentive ends in March 2022, with no direct replacement (yet) announced.

Though, the upcoming Boiler Upgrade Scheme (opening in spring 2022) looks set to give people support for ground source heat pumps, so this is something to keep an eye out for.

Property size (no. of rooms)Appliance and installation costGroundwork for horizontalGroundwork for vertical
2£16,000£3,000£6,000
4£21,000£5,000£13,000
6£32,000£8,000£20,000
7+£42,000£12,000£30,000

Please note, these costs are representative and do not reflect exactly what you might pay. Ground source heat pump installations are always priced on a case-by-case basis.

 

A breakdown of the costs

 

How much a ground source heat pump costs depends on a number of factors. These include:

  • The size of your property
  • How insulated the property is
  • The size of the heat pump
  • Whether it’s a vertical or horizontal ground source heat pump
  • RHI payments (lasts until March 2022)
  • How much support you can get from the Boiler Upgrade Scheme (coming spring 2022)

 

Considering the above, the installation process of a ground source heat pump will also focus on the heat loss of your property. A property that is efficiently insulated will require a smaller heat pump, because it’ll require far less energy to heat your home (and to keep it warm).

Older properties and those with poor insulation will need a larger ground source heat pump to warm them, which will of course increase the upfront cost.

 

Soil type

 

The type of soil can impact the price too. This doesn’t have anything to do with installing the ground source heat pump itself, but rather the type of soil affects something called ‘thermal diffusivity’. Thermal diffusivity is, in layman’s terms, the soil’s ability to hold and transfer heat.

Higher thermal diffusivity means your ground source heat pump won’t need to work as hard, because the ambient temperature is higher than if the soil had a lower thermal diffusivity. Basically then, having soil with high thermal diffusivity means you won’t need to spend as much on a larger geoexchange system to capture the ambient heat.

 

Why are air source heat pumps cheaper?

 

Air source heat pumps are cheaper than ground source heat pumps because they’re simply far less complicated to install. Unlike ground source heat pumps, you don’t need to install piping underground, which requires extensive work to do.

With air source heat pumps, as long as your home is properly insulated and has appropriately sized radiators, you usually only need to pay for the unit itself. And even if you do need additional work (i.e. installing better piping in older properties or underfloor heating), it’s still cheaper than the work needed to install a ground source heat pump.

Looking at the pricing table above, you can see the money needed to install either the horizontal or vertical ground source heat pumps, both of which are more expensive than the installation process for air source heat pumps.

However, because an air source heat pump is exposed to the elements, it’ll almost certainly need replacing before a ground source heat pump. If properly installed, the infrastructure for a ground source heat pump can last 70 years or more!

Ground source heat pump running costs

 

Compared to a gas-powered boiler, ground source heat pump running costs are substantially lower. In an average home, annual running costs for a ground source heat pump are between £460-£680 per year. By comparison, a gas-powered boiler in the same type of property can cost you up to £1,250 a year. Ground source heat pumps are the clear winner here in terms of running costs.

The reason is their efficiency. Even though ground source heat pumps use electricity, which is more expensive than gas, ground source heat pumps often reach an average efficiency of between 300-400%. Compared to the efficiency of boilers at 70%, ground source heat pumps make much, much better usage of electricity.

How popular are ground source heat pumps in the UK?

 

There’s no doubt that ground source heat pumps have increased in popularity in the UK, though some argue it’s not enough. As of 2019, there were just under 37,000 ground source heat pumps operating in Britain, up from roughly 20,000 in 2013. It’s an increase sure, but not enough to start reducing the UK’s carbon footprint significantly.

However, ground source heat pumps are slowly becoming more accessible, thanks in part to government grants aiming to reduce the entry price point. People are becoming more conscious of their impact on the environment too, so some are willing to pay the upfront costs to become more sustainable.

What is clear is that ground source heat pumps will start to increase dramatically after the Government’s ban on gas-powered boilers for new build properties in 2025. Their Future Homes Standard, which will come into effect in 2025 too, is expected to ensure homes are futureproofed with sustainable heating solutions. Naturally, this includes ground source heat pumps!

Illustration showing the different types of ground source heat pump installation

Are costs expected to decrease?

 

Whether the cost of installing a ground source heat pump will decrease depends on the type of installation. If it’s a vertical installation, then right now the highly specialised process needed to drill a borehole means prices are unlikely to decrease any time soon.

Horizontal installations are different, because they don’t require anywhere near the same level of equipment and as more installers are trained, the costs will lower. Also, if you’re willing to dig the required trenches yourself, you can save money, though we’d always advise using a professional instead.

It’s also likely that government grants will continue to expand, which will make it more affordable for people to install a ground source heat pump.

Next steps

 

Ground source heat pumps absolutely represent the future of sustainable home heating – it’s just a case of increasing accessibility. As long as the UK government continues to support grants for the technology, and ensures they don’t pivot back to boilers, ground source heat pumps will slowly but surely become a mainstay in our homes.

Tom Gill Writer

Tom is a big fan of all things eco and has a passionate interest in how technology and localised projects can work together to make the world greener.

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