We have obtained a great final air test result. The contractor, Byram Construction, had not built a Passivhaus before, but the timber frame construction built off-site ensured a factory-controlled build quality with the panels and floor cassettes rapidly craned into place on site with pre-fitted airtightness membranes. The follow on taping of the membrane was meticulously carried out by the site manager.

Good air tightness is essential for low energy buildings, not only protecting the structure from internal moisture movement but reducing energy loss through uncontrolled infiltration.

Eco Test Limited carried out all the air tests. The building is pressurised and depressurised at a range of pressures between 35Pa and 65Pa and the final result was 0.3 ach at 50Pa. 

The final air test ensured we were able to meet the Passivhaus Classic standard for this dwelling, with an annual energy demand of 15kWh/m2/a