The Flemish, Brussels and Walloon regions of Belgium have introduced the airtightness of buildings determined by fan pressurization tests in their regional Energy Performance (EP) regulations. Airtightness testing is not mandatory; however, when using the result of an airtightness test instead of the default air permeability value (for heating calculation)  = 12 m³/ (h.m²), a substantial improvement in energy performance can be achieved…Read more