General on energy efficiency in buildings

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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

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

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

To some extent yes. A collection and analysis of some data collected through the ASIEPI partners has been presented at the 2008 BlowerDoor conference (Papaglastra et al., 2008). However, caution should be exercised when comparing airtightness values : - the measurement methods are not necessarily the same. EN 13829 mentions two methods (A and B) that can lead to very different results e.g., depending on how combustion appliances are sealed; (*)
Post date: 12 Δεκ 2008
Type: Ask the Experts

To our knowledge, only two low-energy labels include a minimum requirement for low-energy buildings: - the PassivHaus standard (www.passivhaus.de) that requires an airtightness better than 0.6 air changes per hour at 50 Pa (n50 <= 0.6 ach); - the BBC-Effinergie standard (www.effinergie.org) that requires for an individual house an airtightness better than 0.6 m3/h per m2 of cold surface area at 4 Pa (this translates for an individual house to a n50 of about 2.5 ach).
Post date: 12 Δεκ 2008
Type: Ask the Experts

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 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 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