Humid air isn't right when I have asthmatic or allergic to dust mites as they thrive in a humid environment, so it's worth investing in a dehumidifier. Extract the moisture to around 50 to 55% Relative Humidity. With this assumption, you can safely run your dehumidifier for about 12 hours a day. The dehumidifier removed musty smell from 2nd bedroom, and I couldn't believe the amount of water that was collected, no musty smell any more. Fantastic product & excellent Customer service also.. It has improved my Sinus condition also and helps to make sure you get a good night sleep. I am delighted that I purchased this product. My room is smell fresher already. I want to add that my friend has a dehumidifier from this company for a year now and it's never skipped a beat and remains one of the best things I ever bought.