How do GSHPs work?
The average ground temperature just below the surface in the UK is between 8ºC and 13ºC. This temperature remains constant throughout the year. Ground source heat pumps (GSHPs) take advantage of this heat to provide space heating and hot water.

GSHP systems circulate water or other liquids through pipes buried either horizontally or vertically in the ground. The water in the pipes is at a lower temperature than the surrounding ground and so it warms up slightly. This low grade heat is transferred to a heat pump, where it is used to heat up a refrigerant. By compressing this 'warmed' refrigerant, further heat is generated and the temperature of the water output from the heat pump is typically 45ºC - 50ºC for space heating and up to 60ºC for domestic hot water.

How much do they cost? And is there any funding available for them?
Funding for social landlords for GSHPs was available through the Clear Skies programme and continues to be available in Scotland through the SCHRI (http://www.est.co.uk/schri/).

Powergen have put together a GSHP ‘package’ specifically for social housing as part of their EEC work. The package consists of the kit you will need (ground loop, heat pump and hot water cylinder) and is designed to meet all the space heating and hot water needs of the property. It comes in 2 sizes, 3.5kW for £2000 and 5kW for £2500.

Powergen are now offering ‘kit plus installation’ for a discounted, fixed price of £4500 (3.5kW) or £5000 (5kW). You need to have a minimum of 6 properties per site and the fixed price might not apply for certain sites (e.g. if it is very inaccessible). This price does not include the internals or connection of the hot water cylinder and this discounted price does not apply if you use grant funding (e.g. SCHRI) towards the cost of the kit or installation.

NB. There are many manufacturers and installers of GSHPs in the UK. However, in our opinion the HeatPlant package represents the best option for social landlords at this time. It is this system that has been installed by Penwith Housing Association and Metropolitan Housing Trust.

What types of property are they suitable for?
GSHPs will, in theory, work in all properties. New-build properties (which have a good thermal performance) are typically suitable. In retrofit the numbers only really add up when the heat demand of the property has been reduced down to a practical level (e.g. though insulation). In addition, these properties need to have an accessible area (e.g. garden) for the drilling of boreholes.

We believe that GSHPs are particularly suitable for properties that are off the gas network, where the generally higher costs of oil, solid fuel or traditional electric heating may leave some tenants vulnerable to fuel poverty.

What are typical running costs? And can they help to achieve Affordable Warmth?
Monitoring data has shown that running costs are generally lower for GSHPs than for other fuels – even when compared with gas condensing boilers. When compared with traditional electric or solid fuel heating, the difference is generally even greater!

Source: Powergen/ Earth Energy Engineering

Will they provide all heating and hot water for the property?
The Powergen Heat Plant system is designed to provide all heating and hot water for the property.


What do tenants think of them?
Feedback from tenants is generally positive – one tenant from Penwith Housing Association commented that, “This will mean the end of ash and mess from anthracite and coal. There is only a small disruption to the gardens during the work and considerable CO₂ reduction”.

How much CO₂ do they save?
Monitoring data shows that CO₂ savings are achieved even compared with a gas condensing boiler. When replacing a solid fuel system, CO₂ savings of over 3 tonnes each year are predicted.

Source: Powergen/ Earth Energy Engineering