Ground Source Heat Pumps project guide

What is it?

Ground Source Heat Pumps (GSHPs) use heat from the ground to heat your home or hot water system. Designed well, a Ground Source Heat Pump will provide all the hot water and heating a property requires for 365 days a year.

What is it suitable for?

  • If you have space in your garden for a ground loop. It doesn't have to be particularly big, but the ground needs to be suitable for digging a trench or a borehole and accessible to digging machinery.
  • Is your home well insulated? Since ground source heat pumps work best when producing heat at a lower temperature than traditional boilers, it's essential that your home is well insulated and draught-proofed for the heating system to be effective.
  • What fuel will you be replacing? The system will pay for itself much more quickly if it's replacing an electricity or coal heating system. Heat pumps may not be the best option for homes using mains gas.
  • What type of heating system will you use? Ground source heat pumps can perform better with underfloor heating systems or warm air heating than with radiator-based systems because of the lower water temperatures required.

What are the benefits

  • The most efficient heat pump technology

  • Unobtrusive and environmentally friendly

  • Cuts your bills by up to 40% – 60% compared to Oil

  • Can earn you money from Renewable Heat Incentive

  • Costs of installation are covered by subsidy (over a payback period)

How does it work?

Ground source heat pumps (GSHPs) use pipes which are buried underground to extract heat from the ground. This heat can then be used to heat your radiators, underfloor heating system or warm air heating systems and hot water in your home.

A ground source heat pump circulates a mixture of water and glycol (antifreeze) around a loop of pipe, called a ground loop, which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year.

The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.

How does it compare?

Ground Source Heat Pumps:

  • Higher installation costs
  • Ground Source are more efficient - due to constant temperature underground
  • Require a large outside area for loops
  • Efficiency dependent upon soil and rock type
  • Qualify for RHI payments
  • Do not require planning permission
  • Low maintenance

Air Source Heat Pumps:

  • Lower installation costs
  • Air Source are less efficient than Ground Source
  • Require a compact outside area
  • Efficiency is not linked to soil and rock type
  • Qualify for RHI payments
  • Do not require planning permission
  • Low maintenance

Costs & Savings

Costs:

  • A typical Ground Source Heat Pump will cost around £11,000 to £15,000 fully installed, dependent upon the model chosen, and the size of the building.

  • For some Retrofit projects you may also choose to budget for an Underfloor Heating system, which will be more efficient than radiators as they can be run at a lower water temperature

Savings:

  • Independent figures from the Energy Saving Trust suggest in standard 4-bedroom house you should be able to save between £400 to £600 per year compared to an older Gas Boiler and £800 to £1,500 for electric storage heaters.

  • In addition, you should be able to earn up between £2,500 and £4,000 per year through the Renewable Heat Incentive.