Low-energy buildings in Europe - Standards, criteria and consequences - a study of nine European countries.

Abstract: Low-energy buildings are nowadays often used in common speech, for selling or promotion – everything has to be ”low energy”. But how do you know if your house is a low energy building? And how do the manufacturers of the building components know? Is there an official definition, what technical criteria do these buildings have to fulfill? The growing of low-energy buildings causes a demand of compliant products that meet the requirements on performance and quality, but the jungle of definitions makes it hard for manufacturers, especially on an international level. Furthermore it is not always assured if the available regulation considers the consequences of the set criteria. Energy savings should not cause a disadvantage of the indoor environment and people’s comfort and health. To list the currently defined low-energy building types and their regulations, compile the criteria concerning four subject areas with focus on ventilation and to analyze if possible consequences on the buildings indoor climate or on the design of the ventilation system are noticeable. For a better understanding of low-energy buildings and its technical features, theory and definitions have been examined by literature studies. The available standards were collected through the responsible issuers, followed by a compilation and comparison of criteria in the standards and a final analysis of possible consequences, based on the given facts of theory. Almost all nine countries have set standards where low energy buildings are defined. But the level of specification varies severely, both between the countries as between different building types within a country. In many standards the building exclusively is defined by its energy performance – the most definitions considering additional criteria are available in Germany, Austria and Switzerland. The set criteria on the ventilation system are similar, which makes it possible to design components suiting many building types – Though, attention must be paid on sometimes differently defined efficiency rates for heat exchangers. Regarding indoor climate no remarkable consequences, but some differences e.g. regarding airflow rates, whose consequences require further research were found.