Go wth Eddies approach. The walls and furnishings act as a reservoir so if you have the dehumidifier on during the day the walls etc. dry out and tjhen absorb moisture at night, we have an independant humidity meter in the bedroom as well as they DH. The humidity doesn't go up much at night. When you start using a DH the humidity drops quickly until moisture starts to come out of the walls and then the humidity drops more slowly until you get to 30% which is the lower limit of the DH as it begins to ice up at this level. There is no need to have the noise at night it will be fine if yoiu just use it during the day. If you keep an eye on the external humidity you can open the winows when it is lower outside ( and not too cold) and get free dehumidification.