Frequently Asked Questions

You'll find below answers to some of the questions we are often asked. If you still have any queries pleased contact us and we will help you in any way we can.

Q1. How efficient is a heat pump system?

Q2. Why have I never heard of these systems before? Are they new?

Q3. How large are these units?

Q4. Can it supply hot water for the house?

Q5. Can the systems provide cooling?

Q6. Can I use a standard domestic electricity supply?

Q7. I am currently designing a new house that will be extremely well insulated. Would a heat pump system be worth considering and is it straightforward to install?

Q8. My architect suggests I install underfloor heating in my new house. Is this OK?

Q9. I have an older style property. Can I still fit a heat pump system?

Q10. Can radiators be used inside my house instead of underfloor heating?

Q11. Can a competent plumber install a heat pump to run my central heating system?

Q12. Could I install the heat pump outside or in my car-port, garage or basement?

Q13. I have been told long trenches will have to be dug on my land to house ground loops but - my land is too rocky to dig trenches - can I still fit a heat pump system? I don't have enough land to dig long trenches - what do I do?

Q14. How big are the trenches?

Q15. Can I install trenches on a downward sloping site?

Q16. I have a large plot of land but the ground is quite hard. Can I dig a shallower trench?

Q17. I have a large pond. I have a stream. Could this be used?

Q18. Are GSHP systems really environmentally friendly?

Q19. Are Ground Source Heat Pumps dangerous? What about servicing and maintenance?

Q20. How do running costs compare with conventional alternatives?

Q21. Are these systems expensive?

Q22. How long do the ground loops last?

Q23. How are the sections of the loop/s joined?

Q24. Open Loop or Closed Loop?

Q25. Are there different types of heat pump?

Q26. Can I install a system myself?

A1. Modern systems are very energy efficient. For each kilowatt of electricity used to run the heat pump, three to four kilowatts of heat are delivered to the building.

A2. The heat pump is a proven technology. The Irishman William Thomson (Lord Kelvin) first proposed the concept of the air-sourced heat pump for space heating in 1852. Heinrich Zoelly patented the ground source heat pump in 1912, while John Sumner constructed the first large-scale water-sourced heat pump system in the UK in 1945 in Norwich. Around the world, particularly in the USA, Canada, Switzerland, Germany and Scandinavia GSHP systems have been common domestic appliances for several decades. Continuous development has greatly improved their efficiency and reliability. The heat pump is now a proven, cost-effective, safe and environmentally friendly alternative to fossil fuels.

A3. A typical heat pump unit for a domestic dwelling is about the same size as a large fridge.

A4. Yes. Several design philisophies allow a heat pump to provide domestic hot water. Some domestic systems are able to heat domestic hot water via a modern high efficiency indirect water cylinder. An immersion heater can then boost the temperature, preferably at night using off-peak rates.

A5. Yes. Reverse-cycle heat pumps can deliver both heating and cooling. Grant options may be more limited for such systems, however.

A6. Yes. There are a number of heat pumps that have been specifically designed to run on a standard UK single phase supply. However, if you do have access to a three-phase supply, which is essential for the larger units, then this is a preferable option.

A7. Yes, absolutely. Almost all new houses in the UK designed to meet or exceed the 2006 Building Regulations should be able to install a heat pump system. These mandatory regulations have been designed to conserve fuel, reduce heat losses and ensure greater energy efficiency, and so will ensure that all modern properties need less heating. This means that the size of heat pump is smaller, will need smaller ground loops or air handling unit and it will therefore be less expensive.

A8. Yes. Ground source and air source heat pump systems are ideally matched to modern low temperature underfloor heating.

A9. Yes, you can, but your money should be spent first and foremost on improving insulation standards and only then should you consider a heat pump. The cost of a heat pump system is directly related to its size and with heat losses being fairly high from older buildings, this can add substantially to the capital cost of installation. Regrettably, many older buildings can never be made sufficiently energy efficient to use a modern heating distribution system such as low temperature underfloor heating, or low temperature radiators. In many cases, an air source system is likely to be easiest to retrofit to older domestic properties.

A10. Yes, but modern, high surface-area radiators, sized for the typical 45°C to 50°C water temperatures obtained from the heat pump, will usually be required. If your house is well insulated these will often be suitable, but check to see how big they would have to be and the space they would take up.

A11. Only if he or she has had specific training in such installations. Ease of fitting can depend on whether or not the heat pump systems provided come complete with clear instructions and whether all the fittings and pipework are in place for straightforward connection to your central heating system, be it underfloor, or wet radiators. We have highly trained fitters on our team.

A12. Yes, and it normally means the pump is nearer to the pipe connections on your ground loops, which often makes the whole system easier to connect. Some home owners have made up a small, well insulated, external enclosure for the pump unit. In terms of air source, locating in garage or basement is also likely to be more attractive.

A13. If area is too small to use trenches or unsuitable, boreholes can be used instead. A geological assessment will have to be completed in order to specify the number and depth of the boreholes.

A14. A typical heating-only installation for a medium sized, new build detached house would need at least two narrow trenches, each 300 mm wide and 40 to 50 metres long and 1.8 metres deep. The trenches can be straight or curved and laid in any direction to suit your site, providing they are always a minimum of 3-5 metres apart. A standard excavator, such as the type used to dig conventional foundations and footings, can dig the trenches and backfill them after the ground loops have been installed. Your builder and/or digger driver will be able to do this work under the instruction and in accordance with the designed provided. Following installation, and the system is pressure tested and buried, your renewable energy collection system can basically be forgotten. However, its location needs to be recorded to avoid accidentally digging it up.

A15. Yes, provided you can physically dig the trenches, a moderate downward slope is not a problem. Consideration needs to be given to purging air from a system with ground loops higher than the heat pump.

A16. Yes, the ground loop coils can sometimes be laid so that the coils lie horizontally in the trench rather than vertically. This would need a wider but shallower trench depth to at least 1.2 metres. However, this is not as satisfactory as a deep trench in which the coils are vertical and you will need a special slinky configuration and probably longer trenches.

A17. Yes, it is possible to use very large ponds and fast flowing streams as an energy heat source.

A18. Yes. In the UK, there is now a strong move towards alternative technologies that are sustainable and environmentally much more acceptable. By using renewable sources of energy to heat your property you can help to reduce these emissions, particularly when compared to burning fossil fuels such as oil. Most electricity suppliers are now offering 'clean green' electricity from a renewable energy source and, if you use this to power your heat pump, your property will be totally heated from renewable energy with zero carbon emissions.

A19. There are no hazardous gas emissions, no flammable oil, LPG or gas pipes, no flue or chimney and no unsightly fuel tanks. GSHP systems have absolutely NO site emissions. There is no need for regular servicing or annual safety checks and maintenance is very low.

A20. It depends what you are comparing. In a modern, well insulated house, a heat pump system can offer very high efficiency and moderate running costs. An oil-fired boiler would cost considerably more to run, and electric heating would be at least three times as expensive. It is true that, on the basis of current gas prices, the very best modern condensing combi gas boilers may only be a little more expensive to run than heat pumps, but who knows where gas prices are headed? Also, all fossil fuel boilers need regular servicing and maintenance and will typically have a considerably shorter design life than a heat pump.

A21. The initial purchase costs of a heat pump system will be quite a lot more than a conventional oil or gas fired boiler. Air sourced heat pumps are typically the cheapest heat pump solution for domestic applications. However, the initial one-off cost is offset by the lower running costs, lower maintenance and low servicing requirements. There is also the security of knowledge that the majority of your heating and cooling energy comes from out of your ground, pond or the air. This component of the heat is under your control and is essentially free. It is also a sustainable source of energy.

A22. Closed-loop systems should only be installed using high density polyethylene (HDPE) or polybutylene pipe. Properly installed, these pipes will last for many decades. They are inert to chemicals normally found in soil and have good heat conducting properties. PVC pipe should not be used under any circumstances.

A23. Pipe joints in closed-loop GSHP systems should be made by electrofusion. Pipe connections are heated and fused together to form a joint stronger than the original pipe. Mechanical joining of pipe for an earth loop is in some restricted applications an accepted practice.

A24. System choice depends mainly on whether you have an adequate groundwater supply and means of disposal. If you have a relatively large heating or cooling requirement and access to a good aquifer beneath your site, open-loop systems can be most efficient and cost-effective. If your heat demand is small, or if groundwater is not available, either a horizontal or vertical closed-loop system is your best choice. Over a period of years, a closed loop system will require less maintenance because it is sealed, eliminating the possible build-up of minerals or iron deposits. Another option, depending on the site requirements, is an air sourced heat pump, which for domestic and small scale developments may be a cheaper option.

A25. There are different kinds of geothermal heat pumps designed for specific applications. Many geothermal heat pumps, for example, are intended for use only with the higher temperature groundwater encountered in open-loop systems. Others will operate at entering water temperatures as low as -4°C, which are possible in closed-loop systems. Most geothermal heat pumps provide summer air conditioning, but a few brands are designed only for winter heating. Sometimes these heating-only systems incorporate a ground-cooled coil that can provide passive cooling in moderate climates. Geothermal heat pumps can also differ in the way they are designed. Self-contained air-sourced units combine the blower, compressor, heat exchanger and coil in a single cabinet.

A26. It isn’t recommended. Non-professional installations may result in less than optimum system performance, or indeed the wrong type and size of system being installed.