Why does my home feel damp in the summer when my air conditioner is running?

Air conditioners typically remove humidity from the air during the summer; however, there are instances where a home feels cold but DAMP when the AC is running. This usually points to the blower motor in your furnace or a grossly oversized AC. A fan motor that is set at too high of a speed for your AC will cool the air, but moves it too quickly across the evaporator coil above your furnace. This will negate its ability to de-humidify the air, creating a cool but damp feeling in the home.  

An older or builder-grade furnace often contains a PSC blower, or a fixed speed ECM motor. These motors move the air, but lack the ability of a Variable Speed ECM motor to dehumidify during the summer.  A Trane furnace with a variable speed blower will slowly ramp up and ramp down its speed at the beginning and end of each cooling cycle to focus on dehumidifying the air. Trane call this Comfort-R. 

Thus, the ‘bookends’ of each cooling cycle focus on dehumidification – giving you some of the advantages of 2 stage cooling even if you only have a single stage Air Conditioner installed! 

Share This Post

Posted in