This article describes two models developed to predict airtightness in multifamily buildings in a Mediterranean region. They are designed to enable city planners, architects and engineers to estimate airtightness in homes built from 1980 to date (predictive model 1) or prior to 1979 (predictive model 2), when the first domestic energy conservation regulations entered into effect. They are based on a series of readily accessible parameters such as winter severity, envelope exposure, presence of a bathroom window and façade type. The estimated n50 data can be used with energy certification software, which presently envisages the same, non-experimentally quantified mean value for all types of housing. They can also be entered into energy and comfort simulation programs to predict energy consumption and expected indoor temperatures
