A question for HRV owners
 

hey all.
now with this huge drop in temperature, my windows show the obvious signs of condensation and moisture.
I looked at my HRV last night and I noticed that when they installed the HRV 3 years ago, they never actually opened the duct for the house portion, so it was only working at about half capacity as most of the air flow was shut off.
Now that I have fully opened the ducts, hopefully that will help to get more moisture out now.
the question is this, how much condensation do you get out of the hoses?
I have gotten pretty much none since yesterday and just wanted to know if that was normal.
I currently have about 1400 gallons of saltwater tanks going in my house, with an expected final total of about 3000 gallons, so I am not expecting dry windows, but yea, just find it strange that I get no condensation off the HRV.
thanks for the help and input in advance.
Neal

depending on the type of HRV the dampers are adjusted (partially closed) to balance the system.

they were all the way closed and according to the manual, they should have been opened at install.
I think it was just a mistake on their behalf.
thanks for the input though Mark, but I think in this case, they should be opened...I could be wrong though...lol
maybe I should call constructo.

Mine has a hose the exits directly into a floor drain, but there is a loop that always has clean looking water in it so I assume there is a somewhat, steady flow.

The HRV works best with cooler temperatures. If there is some other flow restriction such as plugged filters or outside air inlet, it will not work well. It might even burn out the blower motor. It will drain as the unit pulls condensation out of your house.

Not much condensate, and the flaps might be needed
 

OK, first the flaps -- and HRV is usually installed with 2 flappers to "balance" the air pressure with the outside air. Due to imbalanced duct lengths and other pressure issues, the flaps get partially closed to get the right air pressure.
By all means none of the flaps should be EVERY fully closed, and having one closed would acutally cut the flow down much, much more than half.
IE: if the exhaust air was closed -- the air pressure inside the house would be higher that outside and the incoming air fan would be "working uphill" and not move much air. If you thing of your house as a big long pipe with a fan at both ends and a flap, if you close a flap the air flow drops A LOT.

Next, the condensate -- this depends a whole lot of the humidity of the house air, the outside air and the air temperature outside. I don't get much of ANY other than a few drops a day unless the outside air temperature outside is colder than -10C. Once it hits about -20 outside I start getting around 1 cup a day.
Most of the humidity goes out with the slightly cooled air. Colder air holds less water, but if the inside humidity is 40-50% and then you drop the temp to 0, you will get a bit as the condensate only really happens after the humidity hits 100%.

IE 40% at 22C, dropped to 0C will hit about 90%, if it hits -10C then it goes above 100% and everything over falls out. On my HRV it has a "high" setting and a adjustable "low" setting, which can be hooked up to a humidistat to kick into high if it gets to high.

In the end -- most of the water vapor goes out the vent, not out the drip tray.


As for capacity, I used to have to use a towel to clean out each of my window tracks every 2 days or the water would start running down the wall and soaking the carpet with my 200 gal tank. With the HRV on, If I get fog in my 35 year old metal frame windows -- it means it is colder than -25 outside. You should be able to keep the moisture level down in a house with 3000 gal to a reasonable level --- but you might see a small could form around the outside vent :biggrin: