The team behind the UK’s first energy positive house was remaining optimistic this week despite the goverment’s decision to scrap the zero carbon homes initiative.
The Solcer House in Bridgend, Wales, is said to require no input of energy from outside for 70% of the year, and to export much more electricity to the national grid during the summer than it needs to import during the winter.
“Obviously we’re disappointed by the Government’s decision,” said Cardiff University Professor Phil Jones, who led the project team. “We hope that Welsh building regulations will still require zero carbon housing in due course, and the UK still has to meet stiff overall carbon reduction targets.
“But this house is designed to show mass house builders that zero carbon housing isn’t difficult or costly to achieve and doesn’t require new skills.”
Four Welsh universities were involved in the project, which was headed by Cardiff University’s Welsh School of Architecture. It combines the Welsh Low Carbon Research Institute’s Solcer (Smart operation for a low energy region) programme with the Buildings as Power Stations research carried out by the Specific partnership between Swansea University, Tata Steel, NSG Pilkington and BASF (NCE 27 April)
The house is a three bedroom 100m2 terrace unit with foundations containing locally produced low carbon cement and a structural insulated panel system (SIPS) as walls. A 17m2 transpired solar collector on the south facing wall sits below a 40m2 integrated photovoltaic roof pitch. Windows are high performance, there is a ventilation heat recovery system and a heat pump operating on the heated air from the transpired solar collector during cold weather.
Surplus electricity can be stored in a lightweight lithium-ion battery, and surplus heat in a water store. Insulation levels are so high the hot water requirement significantly exceeds space heating needs.
Constructed in just 15 weeks, the house cost £125,000, but its promoters believe that unit costs would drop below £1,000/m2 if several were to be built at the same time.
Specific chief executive Kevin Bygate added: “It shows that proven, readily available technology can be integrated and optimised to produce a home that’s comfortable to live in, simple to use and earns money as well.”
Preliminary calculations suggest that for every 1kWh the house draws from the grid when solar energy levels fall it exports 1.75kWh during sunny weather. Bygate said that while it would be possible to make the house entirely energy autonomous, “Grid independence is not the best economic answer where the grid is available.
“Effective integration of the best available technologies takes out cost. Building houses like this isn’t rocket science, no special skills are needed, any competent building firm could cope.”
As new technologies become available these could be integrated as well, Bygate said. SPECIFIC will be starting full scale trials of a thermal store “about the size of a large chest freezer” later this summer. This will be capable of retaining summer heat captured by the fascia collector for use in the winter, Specific believes.
“Our next move is to interconnect buildings so they can share energy,” Bygate added. “And we’re looking at applying the same integrated optimised approach to larger buildings as well.”