A Ground Source Heat Pump (GSHP) is another example of a renewable energy system you can have in your home. But what do you need for a GSHP, what are the advantages and disadvantages and do you really save money with them?

How do they work?

It captures heat from the ground which is then released into another location – a house or building – where it can be used for space or water heating. This process works year-round, due to a constant ground temperature of between 8-12C.

GSHP’s extract the heat through a series of loops buried underground. This is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature (between 40-50°C), which can then be transferred to the water in your heating and hot water system via a heat exchanger.

Electricity is needed to power the compressor meaning GSHP is not completely carbon neutral. But, in the right conditions, GSHP can turn 1 kWh of electricity into 3 or 4 kWh of heat energy so they can be a good way to reduce carbon emissions from heating, especially if you source the electricity needed from a renewable source such as solar panels (LINK).

What do you need for a heat pump?

Ground source heat pumps require a large area as the horizontal array is laid usually approximately 1m deep. What’s more, allow 500m2 for a 10kW heat pump in clay soil, and twice that for sandy soil. Permitted development rights allow for ground source heat pumps to be installed without the need for planning permission, providing certain conditions are met. We would recommend checking with your local authority for further advice on planning.

A typical GSHP is the size of a large fridge, so you can have it installed in the house or in an outbuilding; however it is preferable to put the pump close to the collector pipes.

What are the advantages and disadvantages of ground source heat pumps?

The benefits of GSHP are:

• It could lower your fuel bills, especially if you replace more expensive fuel heating, such as oil.
• There’s minimal maintenance required
• GSHP are sometimes more energy efficient than Air Source Heat Pumps (LINK to ASHP explained)
• There’s a potential income opportunity from the Renewable Heat Incentive (RHI)
• Ideal system for underfloor heating and radiators
• Dramatically reduce carbon emissions

The drawbacks of GSHP are:

• Space – do you have room to dig trenches for the loops?
• The heat they deliver is 40-50°C compared to Gas at 60-70°C
• If retrofitting to an existing house, some radiators may need to be upgraded

Are Ground Source Heat Pumps noisy?

This a common question for those considering installing GSHPs and the answer is that noise isn’t a problem. Although there are some components to a GSHP that makes noise, they are less noisy than an old oil boiler. As an example, if you stand one metre away from where the pump is installed, the decibel level is around 41, similar to a conversation decibel level.

How much does it cost to install ground source heat pump?

Typically, a GS

HP costs start from £15,000 to install (excluding groundworks), although prices vary considerably depending on the size of the system. This initial cost will be offset by the reduction in fuel bills. An investment in a GSHP system is an investment for the long term; the groundworks have a design life of 100 years and the GSHP itself has a life longer than any combustion boiler.

As a GSHP uses a small amount of electricity, if you have solar PV panels then the running costs will be even lower.

Do you really save money with a heat pump?

Savings depend on what system you use now, along with many other factors including your typical energy usage and insulation of your house. Taking into consideration a well-insulated four-bedroom detached home, over a year these are the savings you could make:

• £475-535 from an old (G-rated) gas boiler
• £1,210-1,485 from old electric storage heaters
• £995-1,145 from an old (G-rated) LPG boiler
• £695-805 from an old (G-rated) oil boiler

Reference: Energy Saving Trust

Not only do you save money, but also on CO2. Per year you can save up to:

• 2,900-3,300kg on a gas boiler
• 3,500-4,000kg on an LPG boiler
• 4,300-5,200kg on an electric system
• 6,200-7,300kg on a G-rated oil boiler

Reference: Centre for Sustainable Energy

Successful use of HP depends on a variety of factors not least the efficiency of the building itself and what other source of fuel you have available. GSHP’s tend to be better suited to new-build homes, as they can be planned as part of the construction process. However, GSHP are available to anyone with enough land space for installation.

Visit our website for more information on Domestic or Commercial installations. For any queries you may have on Ground Source Heat Pumps give us a call on 01522 803 854 or email us at info@ukalternativeenergy.co.uk