With us, the heater has held 6! When my wife abschaltete him there was a shower of sparks and a loud bang. The mistake was that the lead in pulling ever against a metal duct pushes the Zugschnurr and rubs. The heater is Made in PRC, that is not more than Made in China! There namely a TÜV SÜD printed characters, but I could see the TÜV certificate database is no entry. Furthermore, the previous model is (which looks exactly!) On the black list at TÜV SÜD advertised as illegitimate and not tested !!!! Be careful when buying !!!