All properties are designed with mono-crystalline solar electric panels on the south facing roof surface. By using the ZED energy roof system the design reduces the initial build costs by incorporating the solar electric panels into the roofing material.
The size of this system has been carefully matched to meet the annual demand and storage capacity and still supply a little excess power to the grid during peak production. Export is limited to below 3kW to enable single phase connection. The roof is also eligible for the FITS tariff. The size of the system and storage capacity means that annually, electricity bills will be eliminated.
ZED Roof power station 7.5 kW peak
The properties are designed with a low fabric heat loss of around 2.5kW due to high levels of insulation, triple glazing, high levels of airtightness, thermal mass and maximise passive solar gain. This means that additional winter space heating and hot water can be met by the internal gains and a small integrated MVHR based heat pump. All technologies incorporated are fit and forget, easy to use and low maintenance.
The BRE house has achieved an airtightness of 1.3 ach @50 pascals test pressure on first test without walls plastered. Building Regulations requires 10 ach @50 pa.
The Zero Bills Home at the BRE is only connected to
the grid for 20% of the year and still generates some
surplus renewable electricity to run electric vehicles.