As the costs of electricity and gas continue to rise, combined with the effect that using them has on the environment, more and more people are considering changing over from gas and electricity to renewable sources of heat such as air-source and ground-source heat pumps. But what are they and how do they work? Here at Exeter Heating, as experts, we explain.

Both types of heat pump use the heat that is either in the air or contained in the ground in order to heat your home. It has to be said at the outset that both types require electricity in order to run, but typically for every unit of electricity required they will produce between two and four units of heat. Since electricity is needed, they cannot be said to be 100% environmentally friendly if you use electricity from the mains, However, if you have solar panels then they will not produce any carbon footprint. The heat pump effectively replaces your boiler, so you can throw that out and make some more space as well.

Ground source heat pumps consist of a ground loop – which is a network of pipes buried in your garden – and a heat pump at ground level. You need enough space for our heating engineer in Exeter to install it, and just how much space you will need depends on the size of your home and how much heat you need. You need a garden big enough, and with access for a digging machine. As an alternative, if you only have a small garden, you can have a borehole sunk to a depth of 100m or more, but this may require planning permission.

Whichever you have, a mixture of water and antifreeze – glycol – is pumped through the pipes and absorbs the heat that is naturally stored in the ground. This is then compressed and passed through a heat exchanger which extracts the heat and transfers it to the heat pump which in turn transfers it into your central heating system. The heat can then be used to heat radiators and hot water, or an underfloor heating system.

A ground source heat pump can increase the temperature from the ground to about 50°C, although the hotter you heat your water the more electricity the pump will use. That doesn’t matter if you are using a renewable electricity source.

While a ground source heating system is not cheap to install, you can get financial help from the government towards the installation costs. However, once installed, if you are using solar panels to produce your electricity you have a heating system that will cost you nothing to run.

You should note that a heat pump works at lower temperatures than a traditional boiler, so having your home properly insulated is important.

An alternative to a ground-source heat pump is an air-source pump. This works in a similar fashion, but rather than extracting heat from the ground it extracts it from the air. An air-source heat pump is about the same size as an air conditioning unit and is placed either at the side or the back of your home. There are two types of air-source heat pumps – air to water or air to air.

An air to water heat pump takes heat from the air and works something like a refrigerator in reverse. It takes the low-temperature heat from the air and transfers it to a liquid and the heat pump compressor increases the temperature. In the condenser, the heat from the liquid is transferred to your heating and hot water systems. The heat is at a lower temperature than a conventional boiler, so you may need to install larger radiators or an underfloor heating system.

An air to air heating system takes the heat from the air and increases it in a similar fashion but feeds it into your home using fans. This type of system cannot heat your water.

According to the Energy Saving Trust, the savings that you can make can be anything from £400 a year to £1,350 a year depending upon the heating system that you are replacing.

If you would like to know more about ground-source or air-source heat pumps, give us a call at Exeter Heating and talk to one of our experts.