Air conditioning, cooling, ventilation, air infiltration

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Measuring or evaluating the airtightness of multi-family buildings is challenging as there may be technical and practical difficulties that prevent from pressurizing the whole building. These difficulties include for instance building configuration (e.g., exterior hall ways that do not allow pressurisation from a single point), pressurisation fan size, stack effect, or cost. Therefore, the measurement of the whole envelope of multi-family buildings is rarely performed in practice. However, several countries use alternate schemes to overcome these problems, for instance:
Post date: 12 Δεκ 2008
Type: Ask the Experts

There is little information on the subject at the moment. A study referenced in a paper written by Erhorn et al. and presented at the 2008 AIVC conference shows airtightness values of 31 “Passivhaus” houses at commissioning and 2 years later. The average n50 at commissioning and 2 years later were 0.37 and 0.46 ach at 50 Pa, respectively.Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)Date: 2008/12/12
Post date: 12 Δεκ 2008
Type: Ask the Experts

The SAVE-DUCT project has shown that there are large discrepancies between countries on this subject (the project report is available through AIVC at www.aivc.org). Analyses performed on measurements results have shown that Belgian and French ductwork systems were typically 3 times leakier than Class A whereas Swedish systems commonly complied with Class B (i.e., 3 times tighter than Class A).
Post date: 12 Δεκ 2008
Type: Ask the Experts

There are three major ways to estimate this impact: - the simplest is to evaluate the infiltration losses based on a rule of thumb established by Drubul in 1988 (*) and suggested by Kronvall (**) in 1978. The rule says that the infiltration airflow rate in air changes per hour may be determined by dividing the n50 value by an empirical coefficient that lies between 10 and 30. In practice, the empirical coefficient is often set to 20 (i.e., the infiltration airflow rate is equal to the airtightness at 50 Pa divided by 20);
Post date: 12 Δεκ 2008
Type: Ask the Experts

Now in Europe, many countries have adopted the n50 value (i.e., the leakage flow divided by the volume) for their EP regulation while others (e.g., Belgium, France, UK) use the envelope area normalisation. The rationale behind this latter choice lies in the fact that the volume is not needed for an energy performance calculation. Using the n50-value should require a precise definition of the way the volume is calculated, which to our knowledge, is not the case in any European country. On the other hand, the envelope area is usually well-defined in regulations.
Post date: 12 Δεκ 2008
Type: Ask the Experts

There exists a certification scheme in Germany which is not compulsory to perform tests. There exists a compulsory authorisation process in France for technicians who perform test on BBC-Effinergie buildings. To our knowledge, there is no other certification or authorisation scheme in European countries. Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon) Date: 2008/12/12
Post date: 12 Δεκ 2008
Type: Ask the Experts

The airtightness measurement of single apartments is usually performed the same way as in individual houses. Therefore, there is no specific protocol to balance the pressure between the apartment under test and other apartments. Different protocols may lead to very different results. Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon) Date: 2008/12/12
Post date: 12 Δεκ 2008
Type: Ask the Experts

To our knowledge, the UK is the only country that has made testing mandatory. This has been in force since 2002 for large buildings and extended to most buildings in 2006. Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon) Date: 2008/12/12
Post date: 12 Δεκ 2008
Type: Ask the Experts

Energy wastage due to envelope leakage has been estimated in various countries through numerical simulations: - in Belgium and in Germany, the energy impact has been calculated to be about 10% of the energy performance level for individual houses; - estimates based on simulations on 9 real buildings in France lie between 0.5 and 15 kWh-pe/m2 per year (depending on climate, ventilation system type, and building configuration), with an average of 6.6 kWh-pe/m2, between “default” and excellent airtightness
Post date: 12 Δεκ 2008
Type: Ask the Experts

Post date: 1 Μαρ 2007
Type: Publication