Moved to a new location, new house with a dedicated HT room! But, now I'm at 4700 feet, so according to the manual I should be using the high alt setting (W9000), only thing is is gets objectionably noisy after a while. Could I get away with just leaving it at the normal setting, or do I risk damage due to overheating? Ambient temp in my HT room nevers exceeds 76, and relative humidity is very low, usually around 20%. My filter is clean, I wonder if the fan needs cleaning too.