Ground source heat pump costs and savings

A ground source heat pump can cut your carbon emissions significantly. We explain how much a ground source heat pump costs and what to think about if you're considering getting one installed. 

The majority of heat pump installations in the UK are of air source heat pumps. Ground source heat pumps can be more efficient than air source heat pumps in areas that often get very cold, because the ground temperature is frequently warmer than the air temperature. Ground source heat pumps are also vastly more expensive though. 

Read on to find out more, or head over to our guide to air source and ground source heat pumps if you're not sure which type you need. 

How much does a ground source heat pump cost?

Buying and installing a ground source heat pump can cost as much as £28,000 if your ground loop is buried in trenches, or £57,000 if you need to dig a borehole, according to the Energy Saving Trust. 

The payback period (the time it takes for the cost of the system to be recouped in energy savings) will depend on how efficiently your system works, the type of system you're replacing, how well insulated your home is, how efficiently you use the system's controls, and how you'll be using the heat generated from the pump. 

Financial help is available via the government Boiler Upgrade Scheme (England and Wales) or the Home Energy Scotland Grant and Loan. This probably won't cover the full cost of a ground source heat pump, however. 

Find out more about: the Boiler Upgrade Scheme and how to apply.

How to calculate ground source heat pump savings

To get a better idea of how much a ground source heat pump would cost to run, and whether it would be cheaper than your existing heating system, you can make a rough calculation using your own data.

We've worked out an example, below, for a typical household currently using a gas boiler.

Existing heating and hot water costs using gas

Energy regulator Ofgem estimates that the typical household gas consumption is 11,500 kWh a year. 

Gas used for cooking makes up around 2.5% of the total (287.5 kWh). 

That means that, in this illustrative typical household, the quantity of gas used for space and water heating is 11,212.5 kWh a year.

From April 2024, the average price cap for gas is 6.04p per kWh with a standing charge of 31.43p per day 

The annual cost of gas used for space and water heating is 11,212.5 x £0.06 = £672.75

From April 2024, the average gas standing charge is £0.29 per day, so the annual standing charge cost is 365 x £0.29 = £105.85.

That means the total gas bill for space heating and hot water for a typical household (excluding cooking) is £778.60

What's your heat demand?

To calculate the cost of running a heat pump, you need to know your household's heat demand. This isn't as simple as using your current annual gas consumption – you also need to know your boiler's efficiency.

New A-rated gas boilers must be a minimum of 92% efficient; however, that the actual in-use performance is often lower than this. Older boilers are also less efficient. 

For our example calculation, we've assumed that our illustrative typical household currently has a boiler with an average 85% efficiency.

The household's current gas consumption is 11,500 kWh, as detailed above, but only 85% of that is being turned into heat. The actual heat demand is therefore 11,500 x 0.85 = 9,775 kWh.

Potential heating and hot water costs using a heat pump

A typical ground source heat pump can generate 3.5 to 4.5 units of heat for each unit of electricity it uses. We've assumed a COP (Coefficient of Performance) of 4.0 (i.e. 400% efficient) for the following example. 

To deliver the heat demand of 9,775 kWh, the amount of electricity required will be 9,775 ÷ 4 = 2,443.75 kWh.

From 1 April 2024, the average price-capped per unit price for electricity is 24.5p/kWh, so the annual cost of electricity for heating and hot water is 2,443.75 x £0.25 = £610.94

We've assumed that all households already pay the standing charge for electricity, so there's no need to add this.

Which is cheaper – gas boiler or ground source heat pump?

In this example, the ground source heat pump is cheaper to run, saving £167.66 a year on average. 

If your gas boiler is less efficient, or you install a more efficient heat pump, then you will see greater cost savings by switching to a heat pump. 

Changes in energy prices will affect future comparisons. If the unit price of gas rises more quickly than the unit price of electricity, then the cost benefit of a heat pump will be greater. 

Calculate your own savings

Firstly, work out how much you currently spend on your gas heating. 

You can find your fuel consumption (in kWh) on your energy bills. If you use gas for cooking, deduct around 2.5% to calculate how much is used for heating and hot water.

[annual gas usage (kWh)] x 0.975 = annual heating and hot water (kWh)

Multiply this number (in kWh) by your energy provider's price per kWh for gas - this will tell you how much you currently spend on gas in a year for heating and hot water. 

[annual heating and hot water (kWh)] x [gas price per kWh (£)] = current annual spend (£)

Next, work out your heat demand. This is the number of kWh you use in a year multiplied by your boiler's efficiency. If you know your boiler's efficiency, you can use that figure. If you know the make and model, you can check the efficiency in the product characteristics database. New gas boilers must be at least 92% efficient, but an older one may be much less efficient. 

[annual heating and hot water kWh] x [boiler efficiency eg. 0.85] = household heat demand (kWh)

The efficiency of a ground source heat pump is typically between 3.5 and 4.5. If you're thinking of installing a specific model, you can find the COP in the manufacturer's product specification.

To find out how much a heat pump might cost to provide the same amount of heat as your gas boiler multiply your heat demand by the efficiency of your chosen heat pump

[household heat demand (kwh)] x [1 / heat pump COP eg. 4] = [annual electricity usage (kWh)]

To work out what this would cost, multiply it by your energy provider's electricity rates.

[annual electricity usage (kWh)] x [electricity price per kWh (£)] = [annual electricity cost]

Fuel prices: From 1 April 2024, the average capped price for gas is 6.04pkWh and electricity is 24.5p/kWh, but this varies by region and payment method, so check your bills to find your own unit prices.

What other costs are involved in buying a ground source heat pump?

If you plan to replace your gas boiler with a ground source heat pump, you may also consider swapping your gas cooker for an electric one. Retaining a gas supply just for cooking will mean the standing charge is disproportionately high. 

If you terminate your gas supply, you may have to pay for removal of the meter. The cost varies according to supplier. If you don't remove the meter, you must continue to pay a standing charge.

Should I buy a heat pump? 

Ground source heat pumps work best with underfloor heating, which requires lower flow temperatures than radiators. The heat produced by a ground source heat pump is at a lower temperature than other forms of heating.

Our underfloor heating guide can help you to decide if it's right for your home.

Ground source heat pumps are generally better suited to new-build properties than retrofitting to an existing home. This is because costs could be reduced if the heat pump is included as part of the building's specification, rather than having to fit underfloor heating later on. 

If you want to retrofit an existing home with a ground source heat pump, you may be able to get a grant to help pay some of the cost of replacing an old heating system.

A well-insulated house is essential to making the most of the heat generated by your ground source heat pump. Otherwise the heat escapes more easily.

Even if you have a gas boiler, insulation is crucial for making sure you're not paying for heat that is simply escaping. Head to our insulation guides to find out more.

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Running costs can be higher if you're also using the system for your hot-water supply, and you may require a supplementary electric immersion heater to keep up with your heating needs. Find out more in our dedicated guide to electric immersion heaters.

The ground loop element should need little maintenance once it's in place. They usually come with warranties of two or three years, but should operate for 20 years or more.

Whether or not you decide to get a ground source heat pump, it's worth making sure you're on the best energy deal for you. Use Which? Switch, to compare gas and electricity prices.

Getting your ground source heat pump through a manufacturer

While energy companies like British Gas, EDF, E.ON and Octopus sell air source heat pumps from major brands, they don't sell ground source heat pumps. 

The following companies sell and install ground source heat pumps:

• Kensa 
• Vaillant 
• Viessmann 

Vaillant sells flexoTHERM heat pumps which are ground source but convertible to air or water sources too. 

We advise following the lead of an MCS-certified contractor who will recommend an appropriate model and size after assessing your home. They may also be able to apply for a government grant on your behalf.

Getting your ground source heat pump through a private installer

If you want to find an independent installer to help you scope a ground source heat pump and pick a model, find an MCS certified contractor who will be able to apply for a government grant on your behalf.

Installers certified by MCS agree to follow a code of conduct known as RECC (Renewable Energy Consumer Code). This means they should not use high-pressure selling techniques, nor should any subcontractors they employ. 

This should save you from misleading selling techniques like unrealistically high initial prices with time-limited discounts, a technique which would give a seller leverage to negotiate a bad deal for you.

Other examples of conduct forbidden by RECC includes exaggerating a heat pump's performance or withholding information that might affect your decision to buy one. 

There's a need for more heat pump installers in the UK because it's still a developing market. Compared to installing a boiler, it's labour-intensive work that requires more people and more days for installation.

We recommend seeing if there's a vetted Which? Trusted Trader operating in your area. If not, the MCS database is a good way to find a private installer.