First published in Cleantech magazine, July/August 2010. Copyright Cleantech Investor Ltd 2010
By Dr Denis Gross
The point beyond zero energy consumption (when solar and other forms of home-based microgeneration balance the external energy imported), the point at which a house generates more energy than it consumes over a period of time, defines the EnergyPlus House.
The energy consumed by different types of housing differs significantly. In the UK, for example, an average semi-detatched house consumes around 22,000kWh/yr. Over 80% of this typically goes on heating; the remainder on electricity. A low energy house, on the other hand, consumes just over one-third of the total energy of the average house, with only 60% of this lower figure going on heat. The heating requirements of higher efficiency buildings, such as the ‘passive house’, are significantly lower again.