Quote:
Originally Posted by Exeric
Well, that answers that. It seems to imply the humidity filtering only occurs in one direction - outside to inside. Too bad.
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Well, the way it works is that as the higher temperature air, with it's load of water vapor, moves across a higher-to-lower temperature gradient, as the air temperature changes, if it crosses the dew point, will causes the vapor to condense and become water.
If you have a HRV, the water stays on the side of the barrier on which it condenses, and exits, usually through a tube to be disposed.
If you have an ERV, the barrier is permeable, and the water crosses through the barrier and evaporates into the air in the lower-to-higher temperature gradient.
I was very careful with my language to avoid words like "inside" and "outside" so that the description would be valid when read for heating as well as air conditioning.
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So, if you wanted to ventilate AND save heat in a bathroom/shower, you would NOT use a ERV, as that would send the water vapor back into the loo. So in that case the proper choice would be a HRV.
-AC