Sometimes we do things with one goal in mind and find that we get the opposite, unintended result. Such experiences have been all too frequent in my consulting practice in a coastal environment. In the process of trying to do a better job of controlling indoor residential humidity, we actually can make the situation worse. In fact, many times things get so bad, occupants are forced to move out and expensive remediation is required.
ASHRAE recommends we keep our indoor humidity below 60 percent and our thermostat at or above 75˚F for indoor summer comfort. New high-end residential equipment is designed to make 75˚ more comfortable by offering a dehumidification option. We are much more comfortable with 55 percent relative humidity (rh) than 65 percent, given the same sensible temperature of say 75˚. Weathermen call this the “real feel” temperature. Plus, lower humidity prevents mold from spawning. So great — we can now control temperature and humidity, and most of the time the theory works.