Energy efficiency of appliances within sustainable homes is very important as they are a significant source of heat as insulation levels increase. This may seem unimportant during the winter months as they are an extra source of heating, reducing the load on your heating system. However, during the warmer months of the year they can contribute to an overheating risk and consume unnecessary energy.
Heat recovery ventilation is a very important part of low energy sustainable construction. It allows the continuous supply of fresh air without losing the heat from the air that is extracted from bathrooms and kitchens. In the middle of winter some systems return 10 kWh of heat in the incoming air for every 1 kWh that used to run the fans, efficiencies that heat pumps can only dream of!!
In a ‘conventionally’ ventilated home the ventilation comes from drafts, open windows, trickle vents and extractor fans. These methods are occasionally effective at providing the required amount of fresh air but they do not recover any of the heat lost from the outgoing air. This means that just to heat up the incoming fresh air your heating system may be supplying several kilowatts of heat, before accounting for the heat lost through the doors and windows, walls and roof.
If you want to find out more about how to effectively manage your sustainable building project, check out The Self-Build Series. This series of guides has been put together to you understand sustainable construction. We hope you find them useful!