Ground Source Heat Pumps

The Boiler Upgrade Scheme was introduced by Ofgem to replace the Renewable Heating Incentive, to encourage home owners to replace their gas or oil boilers with a more enviromentally friendly, low carbon alternative.

The scheme is open to home owners who wish to upgrade to an Air Source Heat Pump or a Ground Source Heat Pump, and in some cases also covers Biomass boiler installations. It is also open to ‘Self Builders’ who are building their own new homes.

The scheme pays a fixed sum of £5,000.00 towards the installation of an Air Source Heat Pump and £6,000.00 towards the installation of a Ground Source Heat Pump. Where a property is unsuitable for a heat pump and is ‘off the gas grid’, the scheme will pay £5,000.00 towards the installation of a biomass boiler.

Owner eligibility

You may be eligible if you:

live in England or Wales

own your property (whether this is a home or a small non-domestic property)

Private landlords and second-home owners are eligible.

You can still apply if you’ve received separate funding for energy efficiency upgrades such as insulation, doors or windows.

Property eligibility

The scheme is open to domestic and small non-domestic properties with:

an installation capacity up to 45kWth (this covers most homes)

a current energy performance certificate (EPC), with no outstanding recommendations for loft or cavity wall insulation

If you own a self-build property

To be eligible, a self-build must have:

been built mainly using the labour or resources of the first owner

not been owned by a business or organisation

You will need to provide proof to your installer that your property is a self-build, for example a copy of the title deeds.

Excluded properties

Grants are not available for:

social housing

new build properties (apart from certain self-builds)

properties that have already had government funding or support for a heat pump or biomass boiler

Heat Pumps work by extracting latent heat energy from the environment (either from the atmosphere, from under the ground or from a lake or river) to heat a property and produce hot water. The environment around us absorbs and stores heat energy from the sun. This heat energy is stored at low temperatures and in order to make it useful for heating purposes the temperature of this stored heat energy needs to be increased.

In a ground source, or ground to water heat pump, for example, an array of underground pipes, containing a water and glycol based antifreeze mixture, known as brine, absorbs heat from the ground, (at a depth of approximately 1m – 1.2m this heat energy is at a fairly constant temperature of 10 – 12oC). The brine then passes through a heat exchanger within the heat pump and transfers its captured heat energy to a refrigerant gas, which has a low enough boiling point so that the heat energy stored in the brine causes it to evaporate. This evaporated gas then passes into a compressor; compressing the refrigerant gas, causing the temperature to increase.

The compressed gas then passes through another heat exchanger, known as a condenser, where the stored, higher temperature heat energy is transferred into the property to provide heating and domestic hot water. As the refrigerant gas gives up its stored heat energy, it condenses back into a liquid and begins its circuit back around the heat pump.

The compressor and circulation pumps within the heat pump require an electrical supply, but because most of the heat generated by the heat pump is free heat energy drawn from the environment, heat pumps are typically 350% – 450% more efficient, so for every 1 Kilowatt of electricity used, the heat pump will generate 3.5 – 4.5 Kilowatts of heat.

In order to achieve these levels of efficiency and maintain low running costs, heat pumps are best suited to well insulated, new build properties or properties that have been renovated to new build standards and they need to produce flow temperatures as low as possible; typically, between 35oC and 45oC. Because of this, heat pump installations must be designed in unison with the heat emitters, whether they are radiators or underfloor heating.

The advantages of all heat pumps is that they have minimal maintenance requirements, long service lives and when installed correctly will provide very cost effective heating for years to come.

The fluid which is contained within the outdoor underground pipes absorbs energy. This is then transferred via a pump to the heat pump and converted via a process of compression into heated water which is made ready for circulation to warm your radiators or underfloor heating and for use with hot water at your taps.

The cooled fluid (after passing its heat into the home’s water and central heating system) continues back underground to absorb further energy in a continuous loop.

In order to achieve these levels of efficiency and maintain low running costs, heat pumps are best suited to well insulated, new build properties or properties that have been renovated to new build standards and they need to produce flow temperatures as low as possible; typically, between 35oC and 45oC. Because of this, heat pump installations must be designed in unison with the heat emitters, whether they are radiators or underfloor heating.

The advantages of all heat pumps are that they have minimal maintenance requirements, long service lives, and when installed correctly will provide very cost-effective heating for years to come.

The compressor and circulation pumps within the heat pump require an electrical supply, but because most of the heat generated by the heat pump is free heat energy drawn from the environment, heat pumps are typically 350% – 450% more efficient, so for every 1 Kilowatt of electricity used, the heat pump will generate 3.5 – 4.5 Kilowatts of heat.