Heat Pumps

Heat is widely available in the ground, air and water around your house. These natural sources of heat are constantly replenished by the sun, wind and rain. A heat pump system will harness these free and renewable energy sources for heating your house and supplying hot water at a very low cost. The role of the heat pump is to ‘pump up’ heat from a low temperature source, for example the ground under your lawn and release it at a higher temperature into your central heating system.

There are three main types of heat pump available on the market, those that take heat from the ground, from water (rivers or wells) or directly from the air. Ground source heat pumps come in two varieties – vertical bore or horizontal loop.

Existing Dwellings Note - When installing a heat pump into an existing dwelling it is critical to ensure that the building is sufficiently insulated and the existing heating system is surveyed for compatibility. Many times the dwelling’s fabric will need to be upgraded to ensure efficient operation and thus optimal electricity cost. Recommended values of average elemental U-value for insulation would be:

The existing heating system should be surveyed by your installer as not all radiators are suitable for use with heat pumps; it is recommend that Underfloor Heating (with sufficient insulation) or low temperature radiators are used.

Heat pumps are very economical, for every unit of electricity used to power the heat pump, 3 to 4 units of heat are generated. They work best in conjunction with low temperature heat distribution systems e.g. underfloor heating. Because they require electricity to run, they are most cost effective when they can use night rate electricity. This requires a night rate meter. A buffer store is required to maximise efficiency as this allows the heat pump to store heat on a constant basis, releasing it as and when required.

Ground Source Collector - This collector is used in closed loop systems to transfer the heat from the ground to the house. The design and installation of this collector is important and your installer will be able to explain all the relevant aspects of it. It is important not to landscape or plant any trees or shrubs in the vicinity of the collector area as the roots can interfere with the operation of the heat pump. It is important that you take care to note a number of things:

• Your installer will provide a plan of the site showing the collector area and depth. This could prevent damage to the collector if any future work or landscaping is carried out on the grounds. In addition photographs of the collector before it is covered up would be helpful with any future work or trouble-shooting of the heat pump system.
• Collector calculations – Your supplier/installer will carry out tests on the soil to ensure that the most suitable collector (vertical, horizontal) will be chosen. They will provide a formal set of calculations for the collector design which will aid any future troubleshooting.

Air-Source Heat Pump - Air/Air heat pumps take the energy from the air and transfer it to a warm air heating system and Air/Water heat pumps take the energy from the air and transfer it to the water in a heating system.
Water –Source Heat Pump - Water source heat pumps work in a similar fashion to ground source systems and transfer the heat from your water source to the house. Water source heat pumps use an open loop collector. Underground water sources such as a well circulate the water through pipework that in turn transfer heat to your house.
A Piping Schematic, Valve Chart and Wiring Diagram– Your installer will provide you with a piping schematic, valve chart and wiring diagram. This will be very useful in helping with any future work or trouble-shooting of the heat pump system.
Under Floor Heating System Design – You should discuss the under floor heating system and any plans for floor coverings with your installer as they affect the heat transfer from the floor and the overall operation of the system. Again, photographs of the under floor piping system during the installation would be helpful with any future trouble-shooting.

NB for the most efficient and economical operation of your system, it is important that your installer is involved (or well informed) in the above 3 points.

Click here to download our leaflet on Heat Pumps

Click here to download our Buyers guide to Heat Pumps

Click here to download our Homeowners Installation Guide for Heat Pumps

Click here to download the Heat pumps product list