Heat Pump FAQs

How efficient is a ground source heat pump system?

Modern systems are very efficient. For each kilowatt of electricity used to run the heat pump, three to four kilowatts of heat can be delivered to the building. The efficiency of an installation is very dependent on the quality of the design and installation. 

The Coefficient of Performance ("CoP") of a heat pump system depends on the design and quality of the installation: from as low as 2 for an air source heat pump system in unfavourable conditions, up to 4 for an unassisted ground source heat pump.

Are heat pumps established technology?

Yes, heat pumps are common, particularly in the USA, Canada, Sweden, Switzerland and Germany. The principles of ground source heat pumps were first described by Lord Kelvin in the 1850s and continuous development since they were first used commercially more than 50 years ago has greatly improved their efficiency and reliability. They now provide a proven, cost-effective, safe and environmentally friendly alternative to fossil fuels.

Can GSHPs provide cooling?

Yes. Reverse-cycle heat pumps deliver both heating and cooling very effectively. Cooling provided by heat exchange with cold ground is inherently more efficient than air conditioning which typically exchanges heat with hot air.

Is a heat pump system suitable for a well-insulated building?

Yes. All new buildings are designed to meet Building Regulations and should be able to benefit from a ground source heat pump. Building Regulations have been designed to conserve fuel, reduce heat losses and ensure greater energy efficiency, in order to ensure that all modern properties need less heating. For a well-insulated building the size of heat pump will be smaller, it will need smaller ground loops and will therefore be less expensive. 

Is underfloor heating a good idea?

Yes.  Heat pump systems are ideally matched to modern warm temperature underfloor heating because a heat pump transfers heat at a higher coefficient of performance if it delivers to a large warm water circuit (like underfloor heating) rather than a small high temperature circuit (like wall mounted radiators). 

Can ground source heat pumps be installed in older buildings?

Yes, but your building must be well insulated for you to gain most benefit. The cost of a system is directly related to the heat losses, which will generally be higher in older buildings. Money spent on upgrading insulation levels can save a considerable amount on the capital cost of a ground source heat pump system.

Can the heat pump be installed outside or in a basement?

Yes. This normally means the pump will be nearer to the pipe connections to the ground loops, which often makes the whole system easier to connect.

Are Heat Pumps dangerous?

There are no hazardous gas emissions, no flammable oil, LPG or gas pipes, no flue or chimney and no unsightly fuel tanks. Heat pump systems have absolutely NO site emissions. 

Are Heat Pumps noisy?

No, a ground source heat pump makes less noise than a gas boiler.  An air source heat pump external fan unit will make some noise, a little like an air conditioning unit. 

What about servicing and maintenance?

As with any valuable plant a ground source system should be covered by an annual maintenance agreement with the supplier. However, routine maintenace requirements are very low. A heat pump can be expected to last over 20 years – longer than a combustion boiler – and if you have a GSHP, the ground heat exchanger should have a life of over 50 years.

How do running costs compare with conventional alternatives?

A heat pump system can offer very high efficiency and low running costs. Oil-fired boilers cost considerably more to run. Even modern condensing gas boilers are more expensive to run at current gas prices, with gas prices also set to rise. All fossil fuel boilers need regular servicing to maintain efficiency and check safety.

What about alternative heat sources for heat pumps?

A ground source heat pump uses a ground loop or borehole to exchange heat with the ground: the advantage is that a relatively constant temperature is available throughout the winter if the ground loop is large enough. There are alternatives which can also be attractive for larger buildings including open loop systems which heat exchange with open water or aquifer systems: water source heat pumps or marine source heat pumps. 

What are the costs?

The initial purchase costs of a ground source heat pump system are more than a conventional oil or gas fired boiler. The initial capital expense is offset by lower running costs, lower maintenance and low servicing requirement. There is also the security of knowledge that the majority of your heating and cooling energy comes out of the ground and will not increase in price.