Ground Source Heat Pump and Solar Thermal Installation
Mr and Mrs Lawton, Faringdon
Mr Lawton approached Heelas heating after several recommendations from Heelas clients/trade partners. Mr Lawton had an existing oil fired central heating system which was costing around £2500 per year to run.
With any heat pump installation, the thermal efficiency of the property is key to its efficient running. If the property is not up to current standards of insulation, this is the first area that needs to be addressed before any heat pump installation can be considered.
Heat pumps produce much lower flow temperatures than gas or oil boilers, so the thermal efficiency and airtightness of the proposed property is critical. In general we only recommend heat pump installations in new builds or existing properties that are or have been fully refurbished to current building regulations and insulation standards.
If Mr Lawton's case, his property was a draughty, poorly insulated bungalow with suspended floors and radiators. Our first approach was to discuss with Mr Lawton the possibilities of increasing the thermal efficiency of his property. We recommended that he have modern double glazed window units fitted, the cavity walls be filled with insulation and his entire suspended floor be lifted so that 100 mm of high density insulation could be installed between the floor joists and then the floor relayed.
Mr Lawton was impressed with our overall approach to the job and our recommendations regarding thermal efficiencies/insulation, as he had spoken to other companies who had not even mentioned the important points we had raised prior to the quotation being given.
Heelas arranged for a trusted partner to attend site and give a quotation for insulating the floor and relaying the floorboards, along with a ground worker to carry out the extensive excavations needed for laying the ground loop collectors.
Mr Lawton was keen to go as green as possible, so we specified a Worcester Bosch ground source heat pump (Worcester Bosch Greenstore System 9 kW) and an evacuated tube solar thermal system(Westech 58mm 30 tube). This meant that during the winter the heat pump could heat both heating and hot water and then during the summer the heat pump could be switched off and the solar thermal took over the hot water generation from April through to October.
Part of the job also meant upsizing all of the current radiators to compensate for the lower flow temperatures produced by the heat pump. The whole installation took part over a three-week period and was completed by the end of March 2010.
Mr and Mrs Lawton immediately noticed how much warmer their house was, even when the heating wasn't on due to the increased levels of insulation. Heat pumps are self-regulating with their running periods, which means there is a much more consistent, comfortable level of heat throughout the house.
Heat pump running costs have now been calculated to be between £800-£900 per year and all of their hot water through the summer is produced free of charge from their solar system.