A passive house is an energy-efficient building that has year-round comfort and good indoor climate without the use of active space heating or cooling systems. The space heating requirement is reduced by means of passive measures to the point that there is no longer any need for a conventional heating system.
A passive house provides very high levels of thermal comfort and an even temperature throughout the building. Passive houses are usually light and bright due to large glazed areas designed to optimise solar gains, and are healthy to live and work in due to fresh air supplied by the ventilation system.
The appearance of a passive house does not need to differ from a conventional house.
In the UK some people prefer the German spelling 'Passivhaus' to differentiate a solar passive dwelling from the constuction standards developed by the Passivhaus Institute in Germany. However the Passivhaus Institute set a clear guideline that 'Passivhaus' should be translated in all languages where the principles are being incorporated; e.g in Sweden: 'Passivhus' and in France: 'Maison Passive'. Thus we use the term 'Passive House' or 'Quality Approved Passive House' for a building (residential or commercial) which is designed and built to the set criteria of the Passivhaus Institute.
Since the first Passive House dwelling was build in 1991, this standard has been succesfully implemented in tens of thousands of residential and commercial buildings across Europe. Lots of research and monitoring has been conducted over the last 20 years which has been fed back into the PHPP, the widely accepted energy efficiency design tool for Passive Houses. European funded projects, such as CEPHEUS and PEP examined a large number of projects out of every angle and in various climatic conditions.