This construction standard was “rediscovered” in the early 90s by the German physicist Wolfgang Feist, who worked, studied and built in 1991 in the city of Darmstadt, southwest of Frankfurt, the first modern Passive House. A few years later, in an effort to develop and promote the existence of this standard, he founded the PassivHaus-Institut, which has branches in many countries worldwide and it is the official certification body of all passive houses internationally.
Passive house is an ultra-efficient energy construction, which provides excellent thermal comfort conditions ensuring great indoor air quality; it is affordable and simultaneously meets very high ecological standards. The standard has been characterised as unique and innovative, because while it is based on the principles of Green Building and Energy Conservation, it puts aside attitudes and practices that have to do with using renewable energy sources, ecological materials, recycling-reuse and rational water management and maintains as key pillars the excellent thermal shielding of the building envelope and a smart high-efficiency mechanical ventilation system.
The Passive House is not just a building with low energy consumption, it is something much more. It is a layout philosophy, wherein the need for oil or natural gas ranges from zero to minimum. For this reason it could be described as revolutionary and it conflicts with the huge economic interests of oil and gas exploitation, making them virtually useless in the construction sector. These ultra- low energy buildings have ventilation systems which can produce space heating or cooling only by the incoming fresh air. Due to their incredibly strong insulation, the heating or cooling needs are minimised and can be met by using a heat-exchanger, which is constantly providing fresh air and increases the quality of indoor air creating a healthy indoor environment.
A typical passive house presents the following features:
- Fresh, clean air: HEPA quality air is provided due to special filters. However interior furniture must be carefully selected to minimise indoor air pollution from VOC's.
- Absence of cold "outside walls". The strong thermal insulation provides high resistance to heat flow and there are no colder walls than other walls.
- The same temperature to all the rooms. There are no colder areas in the house.
- Stable temperature: when ventilation and heating systems are switched off, the lose is less than 0.5 °C (1 °F) per day in winter, controlled at around 15 °C (59 °F) in the central European climate.
- Fast adaptation to normal temperature: the indoor air temperature returns to the desired limits in a while after closing the opened windows or doors.
As a result a passive house saves energy by 90% compared to existing typical buildings in Central Europe, or more than 75% comparing with a conventional new construction. The extra cost of the initial investment is only 5-10% more than the construction cost of a traditional house. The absence of an expensive cooling - heating system balance the amount to be spent in excessive thermal insulation of the building envelope and increased ventilation requirements. Finally, the required oil consumption is less than 1,5lt / m2 / year!
In conclusion the "Passive House" is a very reliable model for the construction of modern, healthy, sustainable and energy-efficient buildings with affordable cost.