Passivhaus is an energy efficiency standard, developed in 1988, which sets out various criteria for homes and commercial buildings for maximising energy savings – thanks to its orientation, materials used and insulation, amongst other features.
This standard sets maximum values for energy consumption of space heating, cooling, primary energy usage, as well as the highest temperature inside and the level of air tightness – not allowing virtually any air to leak from the house. These requirements can however vary in different countries due to different circumstances, for instance the age of existing buildings.
Passive houses have to be designed and built precisely to the specifications – for maximum gain. The most important features include the specific positioning of walls in order to capture the most sunlight, or the super air tightness. Despite some myths windows on these houses can be opened but due to excellent indoor air quality, the air ventilation system and other factors it’s usually not needed.
Various materials are used for the construction and even the colour of the outside wall is suggested to improve efficiency through either absorption or reflection. Insulation has to be of highest standard and very thick, both at the walls and the roof.
Meanwhile, heating is hardly required as a Passivhaus also utilises the heat energy generated inside the building, for instance by various appliances. Thanks to the careful design interior temperature does not go below 15C and due to the air tightness there are no cold spots or mould growth inside these buildings.
Lighting solutions are also energy-efficient, thanks to the use of solar-powered lights outside or LED lamps inside – amongst others.
Another great advantage is that such houses can be built in any climate, and there are now over 30,000 such homes all over the world.
Also, the main criticism of being very expensive is addressed by the continuously decreasing construction costs, while savings could be enormous. In the case of a UK office building, the company Interserve in Leicester managed to save GBP 26,000 at their annual energy costs after moving into a Passivhaus.
Thus, passive houses may mean homes of the future for us or our companies, offering significant energy savings, which is also important for our wallets.
For more info, check out: Energy World, March 2012, “Passivhaus in the UK – an alternative to zero carbon”
Written for the Energy Saving Warehouse
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