I have a Daikin Altherma HT (ERSQ011AAY1/EKHBRD011AY1) 11kW heat pump installed about 9 months ago for space heating as well as hot water production.

In the last 1.5 months, the Interior Unit compressor is noisier than usual when it runs. The specs claims that th IU is supposed ot be quiet with a noise level or 43dB. However, I feel that it is much louder as I can hear the compressor running , especially at night in my bedroom, through two wooden doors.

I called the installer in today and he insists that the compressor running noise which was reproduced in his presence sounds like any other installation he has done. I told him that for the first 6 months, the noise was not at this level but he just brushed off my claims. As he said it is normal, no further action will be taken to rectify the "normal" noise. if I insists on changing the compressor, it will be at my expense, althought the compressor has a 3-year warranty.

Does anyone with an Altherma HT unit have the same perception that the interior unit compressor noise is high?

Any suggestion on what I should do next? I live in Geneva, Switzerland.

Thanks!