Sustainable Heating Solutions

Heat pumps

A heat pump is, quite simply, a device which transfers heat from one place to another. A ground source heat pump transfers heat from the ground underneath your garden via a ground loop and transfers it into useful heat in your property. Sometimes bore holes, ponds, or running water sources are used instead of ground loops; these are often more efficient but the principal remains the same.

Heat pumps are available in a range of different sizes to suit properties with differing heating requirements. One of the main restrictions in terms of sizing heat pumps is the capacity of your electrical supply. Heat pumps (particularly ground source heat pumps) often contain large compressors which can put a severe strain on the local electricity supply network. Larger models will invariably require a three phase supply – often an expensive requirement if there is not a suitable supply close to your property.

Heat pumps can be expected to provide approximately 2.5-4kW of heat for each kW of electrical power they consume – so providing an efficiency of between 250-400%.

Heat pumps can be a convenient and efficient way to heat a property if properly sized and installed, but it is important to ensure that your supplier fully understands the nature of your property first. We know of too many occasions where heat pumps have been incorrectly sized and struggled to provide adequate heat. Older, poorly insulated properties can be particularly troublesome as heat losses can be too great for the heat pump and distribution system to keep pace with.

Most heat pumps provide hot water – which then has to be distributed around the property in the same way that hot water from a fossil fuel boiler has to be distributed – usually via a system of pipework and radiators, however because heat pumps are only capable of providing hot water at around 60°C, they require much larger radiators to allow sufficient heat to be dissipated into the room. In practice, this is normally impossible with wall-mounted radiators and so heat pumps are generally only used in conjunction with underfloor heating – which is perfect for the lower-temperature water heat pumps produce.

Air to air heat pumps are starting to become popular in the UK. Like an air source heat pump these units extract heat from the air outside your property but rather than producing hot water, they produce warm air. Because they deliver heat in the form of direct air heating they do not require a distribution system – so are much cheaper to install than other kinds of heat pumps, but do require good airflow within the property. They are an excellent way of supplementing an existing heating system too – reducing your carbon footprint and fuel costs in much the same way as installing a woodburning stove can do. It is important to realise that an air to air heat pump will not provide you with domestic hot water – this has to be provided in some other way.

If you feel that a heat pump might work for you, please contact us to discuss what model might be best for your requirements.

To learn more about heat pumps, please go to the heat pumps page in our Sustainable heating technologies explained section.