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Why are there different indicators (n50, q50, w50, etc.)?

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...
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Is it possible to compare airtightness measurements between the Member States?

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...
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How do you deal with envelope airtightness value in energy losses calculation?

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...
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What is the energy impact of envelope leakage?

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...
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Is ductwork airtightness good in the Member States?

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...
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What are the minimum requirements regarding airtightness for low-energy buildings?

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...
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Is there a database to see which levels of airtightness are compulsory in EU MS, or guidelines?

There is no up-to-date document at this time. Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon) Date: 2008/12/12
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Is there a certification process for the pressurisation test technicians?

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...
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Are there countries where airtightness testing is compulsory?

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...
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Are the methods validated, which are offered for the calculation of energy needs in EN ISO 13790?

The monthly method and the simple hourly method were indeed validated by comparison to detailed calculations and to the actual energy use of several buildings (monthly values). The monthly method for heating has been in use since 1990. (...
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Regarding the methods offered for the calculation of energy needs in EN ISO 13790. What is the difference between the monthly me

This is explained in detail in annex I.5 of the standard EN ISO 13790. The main difference is that the degree day method contains an implicit assumption about the effect of internal and solar gains on the heat balance (independent of the...
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Where can I find background information and more technical information, concerning the content of EN ISO 13790?

Background information on the origin and rationale of the monthly method can be found in Annex I of the standard EN ISO 13790. It also contains more technical information concerning the content of EN ISO 13790, as well as Annex H of the...
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Why are different methods offered for the calculation of energy needs in EN ISO 13790?

Each method has its own applications: the seasonal method is the simplest, but it is applicable only in climates where seasons are clearly defined, the monthly method is easy to use in buildings without or with small intermittence effects...
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How can I make the energy performance of systems visible on the Energy performance certificate (the energy label)?

This is possible if not only the overall energy performance (in MJ or kWh), but also the system energy performance is reported separately. The same goes for the local production of renewable energy. EN 15603 describes how this could be...
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Is there a roadmap or guidance to achieve one European calculation method on the energy performance of buildings?

There is a consensus within Europe that the built environment has a major task to reduce the CO2 emissions and convert to sustainable energy systems. The energy saving targets are high and there is a need to show in a non controversial way...
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Are the products, building products and systems, taken into account in the EPBD standards?

The energy performance of products is taken into account in an indirect way. The EPBD CEN standards are generally dealing with performance description of buildings and systems. The EPBD standards describe the way the system performance has...
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Are the CEN standards delivered as paper documents or as PDF?

This is up to the National Standard Body, most countries offer both possibilities. Question submitted by: Dick van Dijk (TNO, The Netherlands) Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands) Date: 2008/03/10
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What is the difference between EN ISO 13790 and EN 15603?

EN ISO 13790 describes calculation methods for the energy need for heating and cooling for each building zone, whereas EN 15603 deals with the overall energy use and the energy performance of buildings, collating the results from other...
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What are the advantages and disadvantages of the holistic and the simplified approach?

The primary advantage of the more detailed and thus more advanced method (holistic approach) is the higher quality and reliability of the results, due to the very realistic model on which the calculation is based. The intermediate results...