A heat pump is a device which moves heat from one location (otherwise known as ‘the source’) to another location (‘the heat sink’) using an electrical input. This can produce up to five times its own power in heating.

Heat pumps are used in everyday living in the form of a refrigerator. In a domestic refrigerator, heat is extracted from the cabinet to keep food cool and fresh. The extracted heat is then expelled from the back of the fridge through the radiator grill. A fridge, therefore, cools the internal box and the surplus heat produced can be viewed as a ‘waste product’. A heat pump works with exactly the same technology, cooling the outside, whether that be air, earth or water. The ‘waste heat’ produced is then used to provide ‘useful heat’ for use in a building.

Essentially heat pumps can be subdivided into ground source and air source heat pumps.

A ground source heat pump uses the heat available in the ground or water and an air source heat pump uses heat from the ambient air.

Ground source heat pumps are usually more efficient than air source heat pumps because their ‘heat source’ is at a more constant temperature; beneath the surface of the earth the temperature will not fluctuate as much as the air temperature above. Where it might be frosty on the surface, a metre or so below ground the temperature could be around 8oC.

Heat pumps are extremely efficient. Their efficiency is measured in terms of COP (coefficient of performance). With the continual rise in the price of fossil fuels, heat pump running costs are considerably cheaper than that of a conventional boiler.

The essential components are simply those which make up a refrigerator, and with limited moving parts are highly reliable with very low maintenance.

There is no requirement for a flue because the technology is pollutant free with no CO2 emissions. Installation of heat pumps will improve compliance with Building Regulations and Home Information Packs.

Unlike conventional boilers the efficiency of a ground source heat pump does not diminish over the anticipated lifespan of 25 years. The anticipated lifespan of a ground loop array is expected to be well over 50 years.

Reduced VAT – renewable technologies have a reduced tax rate of 5%.

Heat pump installations assist with compliance to Part L of Building Regulations which has been introduced to help meet the Government’s target of a 20% cut in carbon dioxide emissions by the year 2010.

Grants: there are a number of grant options or incentives available depending upon the type of building, the area, the application and which manufacturer is used. (Please see Grants and Incentives).

COP refers to Coefficient of Performance. The COP is calculated by dividing the useful heat output by the energy input which is usually rated as around 4 i.e. for every 1kW of electrical input 4kW of (thermal) output is achieved, essentially meaning that a heat pump is 400% efficient. This can be compared with the most efficient condensing boilers rated at around 91 – 92%.

Please see the following: How heat a pump works

Yes, a heat pump will produce all heating requirements. Heat pumps are ideal for low temperature heating systems which is why they work so efficiently when coupled with a well designed underfloor heating system. They can be used to heat radiators and other convector systems providing they are designed and sized correctly.

There are various ways that a heat pump can heat your hot water depending upon the model of heat pump used. Heat Pumps can provide all of your hot water requirements but an existing hot water tank may have to be replaced with one more compatible for a heat pump.

Yes heat pumps can also provide cooling; after all they are based on the similar technology to a fridge. Cooling can be produced actively or passively although the design of such a system can become more complicated.

Active cooling is when the cycle is reversed so that the building is cooled and heat is ‘dumped’ back into the ground loop. Active cooling works extremely well and is often applied where heat pumps are being used in a commercial situation. Consideration has to be given about the distribution systems with active cooling, such as the use of fan assisted convectors or a ducted air system. Installations of heat pumps which offer active cooling are ineligible to receive a grant.

Passive cooling is where the cooler temperature of the ground loop array is passed over a heat exchanger or directly passed through the heat distribution system. This is a relatively free option only using the power of the associated circulation pump(s).

Passive cooling can be misconstrued and is unlike air conditioning used in cars or commercial buildings. All it offers is for the thermal mass or fabric of the building to be lowered. How effective it is in the UK could be disputed especially with our poor summers and high humidity, but it is an option. Passive cooling should only be applied to projects where a ground loop is made up by boreholes, not horizontal collectors.

Air to air heat pumps (air source) are commonly used to provide cooling.

Yes, heat pumps can heat swimming pools, indoors or outdoors providing the system is designed correctly. This is common practice in Europe.

Yes. Against all fuels, however, the payback period will depend upon which fuel is being displaced, the type of property and the design of the system.

The supply and installation of a heat pump system is expensive compared to that of a conventional boiler but if sized and installed correctly you can make a considerable saving on your annual energy costs.

Heat pumps still require electricity to run but the annual running cost of a heat pump is likely to be around a third of the price to that of oil or less than a third compared to LPG. In addition, there should be little or no added expense for maintenance or servicing.

A heat pump will require a standard domestic single phase supply. They do require a robust power supply but as standard have a built in soft start to reduce the starting surge of the compressor. If a 3 phase power supply is already installed at a property then this may be more preferable and slightly more beneficial.

Heat pumps vary in size. Some ground source heat pumps take up allot of space with their associated parts and it would be strongly recommended that they have their own dedicated area. Areas such as utility rooms, garages or outbuildings would be suitable.

An air source heat pump is mainly located outside close to a building but they can also be installed indoors. The outdoor units can be large and intrusive so consideration has to be given as to where would be the best location so that they get a sufficient air flow, are discreet for aesthetic reasons and noise produced but close enough to bring the pipes through into the property.

The amount of pipe required for a ground source heat pump will depend upon the energy requirement for the building, the nature of the ground/soil and the regional location of the property.

It is important to ensure there is sufficient amount of pipe installed which has been sized to maintain the required flow rates. It would be recommended to leave this calculation to the installer.

For a horizontal ground loop array you can assume the area of land required is roughly one and a half times the area which is being heated but this will also depend upon the heat requirement for the property and the ground loop being used.

If drilling then the area of land required is minimal but the drilling rig will need sufficient access to the land and enough space to manoeuvre.

Horizontally laid ground loops are installed in several ways using different sizes of pipe but essentially it is about getting a sufficient amount of pipe in the ground to provide for the buildings energy requirements.

Different manufactures will specify different types of ground loops to be used. Typically trenches are excavated where the collector pipe is laid up and down or slinkies can be used which are specially coiled pipe work that again gets laid out in trenches. Whole areas can be excavated and pipe can be run up and down creating an ‘underfloor layout effect’ in the ground.

Alternatively ground loops can be installed in bodies of water to take the available heat from the water.

If drilling, when the hole has been drilled to the required depth a collector loop is inserted and the hole grouted up using a thermally enhancing grout. The grout fills in the voids around the loop which helps conduct surrounding heat to the loop.

A manifold is where multiple flow and return pipework is connected and reduced to a single flow and return. Manifolds are sometimes used for flushing the ground loop array and to provide control over the various loops.

Manifolds are used on underfloor heating systems as well as ground loop arrays and essentially provide the same function.

Manifolds used for connecting up ground loops should preferably be located externally to prevent problems with condensation. Manifolds are often located in chambers or are wall mounted where they can be enclosed.

Manifolds used for underfloor heating systems are much smaller and are often boxed in cupboards or installed under the stairs.

A heat pump system can be relatively simple to install but it is the design and application which is critical. Although heat pumps have been in existence for many years it is only recently that they are becoming more recognised with increased public interest. Lack of experience or understanding of heat pump technology is leading to poorly designed systems with bad publicity. CA Heat Pumps recommend that only qualified installers are used.

A heat pump produces no hazardous gas or CO2 emissions on site. The only CO2 emissions produced are those by the power station supplying the electricity. (A heat pump will therefore help comply with Building Regulations).

Yes, grants or incentives are available for installing a heat pump system. (Please see Grants and Incentives).

A perfect scenario is a new build which is highly insulated with underfloor heating throughout and a sufficient area for a ground loop (roughly one and a half times the area which is being heated). However, a heat pump can be installed into most buildings assuming they are being renovated or converted.

Well insulated buildings with a low heat demand are ideal, but for an older, poorly insulated property other improvements should be a priority such as improving insulation standards or ensuring all windows are double glazed.

A heat pump can be installed in any building, i.e. flats, houses, village halls, churches, offices, school, factories, etc. They can also heat swimming pools, in-fact heat pumps are used on the Royal National Lifeboats!

Regulations have recently changed so that ground source heat pumps require no planning permission. If installing an air source heat pump, for the time being you will still have to apply for permission.

If in doubt about planning laws always consult the Local Authority

Minimal maintenance is required for a heat pump.

Although an ‘annual service’ is not really required, heat pumps should not be ignored. There are simple checks to be made which should be highlighted when a heat pump is commissioned by the installer.

Installing a heat pump is straightforward but it is within the design and application of the system where experience is crucial.

CA Heat Pumps has many years’ hands on experience in the design and installation of ground source heat pump systems. Having installed in excess of 85 heat pump systems using 6 different manufactures and various ground loop arrays CA Heat Pumps Ltd is able to advise on the best system and most suitable heat pump for your property.

There are many different options for the most efficient way to extract the heat, and how to set up the installation to a specific property; with the experience of CA Heat Pumps Ltd, not only do you achieve the most effective and complete system for your property but you will also be guided through other aspects of applying this renewable heating technology that might never have otherwise been considered.