Higher sound classes possible also in areas with traffic noise combining high façade sound insulation, fresh air supply and efficient thermal control

Sweden has recently introduced a new governmental regulation, that allows dwelling-houses close to roads, railways and industries. However, they must then provide at least one so called "quiet side", which is defined as a side with LpAeq,24h <55 dB, corresponding to a LDEN of about 58 dBA road traffic noise. However, looking close to the results of 3 questionnaire surveys, it becomes clear that the results presented by the researchers may support new interpretations. The role of the façade sound insulation seem to have been systematically underestimated, as well as the effects of poor indoor air quality and over-temperatures. If dwellings are made to fulfil a set of requirements (high sound insulation, clean air supply and comfortable temperature at all times), they can provide satisfying noise conditions indoors also in areas with heavy traffic where no quiet side can be realized. This conclusion can be suggested for the new international standard on sound classification of dwellings, where the current wording is more conservative.