To tell you the truth, after reading all of the laudatory evaluations and reviews, I did not expect this, but the vents 100 ma, which costs half the price, is superior in virtually every way. The only difference is that the noise level it produces is 36 dB, rather than 34 dB like this one. The setting of Silent is acceptable for the time being; but, if during the summer there is a backflow of air through the ventilation shaft, you will need to adjust it once again because there is not a typical check valve in place.