When it is running at full capacity, the acoustic pressure is approx. 40 db (plus/minus 2 db, depending on solar radiation). This corresponds to the noise from a very quiet extractor fan and we have not yet had any customers who have been bothered by the noise from the SolarVenti. Moreover, the noise level (air flow) can be adjusted using the fans regulator. When the fan is turned down the temperature of the injection air will rise.