Norway is another example of a country where good products are used (predominantly round ductwork with pre-fitted gasket seals, giving leakage class C) without any explicit requirement in the building regulations, and where duct leakage is not taken into account in the energy performance calculations. The reason for this is historic. Up until maybe 15 years ago, Norway had explicit requirements in its building trade specifications, just as Sweden, but this is no longer deemed necessary because almost all products on in the Scandinavian market are quality airtight ductwork anyway.
For more information you can check-out the following:
- Information Paper P187 “Duct System Air Leakage — How Scandinavia tackled the problem” by P.G.Schild & J.Railio, on the BUILDUP website
- Final technical report from project ASIEPI, Work Package 5, see www.asiepi.eu