DIY Heat Recovery Ventilator ?

[Doug]

Originally Posted by bassman

You are probably right. I do live in a older home that is far from sealed but I intend to remedy that soon.

It will be a little while before I get to the HRV step so I still have lots of questions to ask and things to learn.

If I know me I will just bite the bullet and buy one when the times comes, I like sleeping at night. LOL I am just poking around to see if any one has come up with a cheaper solution.

If your climate is warm enough there to just vent, which is basically an air exchanger, {w/no heat recovery}, some of the west coast guys with large systems had some really good venting designs with pics. And if you're interested in some good HRV threads, I believe I mentioned we had a few dandys.

[rdnicolas]

Originally Posted by bassman

I am not as concerned about removing the moisture from the air as I am in removing the moist air all together, moving it outside. I have thought about a coil, still might do something like that too.

How cold do the winters get over there?

During the winter, the humidity may not even be an issue unless you are having condensation at your windows. In this case reducing outside air to a minimum is usually desired as it generally means more heating dollars for your wallet. For typical residential homes, the combination of outside air introduced from your furnace and the inflitration from the building envelope is sufficient for code required ouside air ventilation rates.

For many aquarium keepers that don't run carbon all the time, elevated tank odors, which become more prominant with higher humidity (I'd guess above 50%Relative Humidity) can be exhausted outside from the house.

This creates an issue with beneficial heat lost from the house. Moist air will have a higher heat capacity and exhausting this heat entirely becomes a huge energy waste as the air exhausted outside will be replaced with cold -30degree air entering your house which will need to be heated by your furnace.

Enter the HRV. The Heat recovery ventilator is designed to recoup some of this otherwise lost heat energy by crossing (counterflow) the exhausted and replacement airflows with eachother. During the summer, your temperatures in the house will typically be hotter than outside unless you have inhome air conditioning. This makes the HRV useless, thats why there is a bypass to prevent the two airstreams from crossing during these conditions.

So why the long winded text?

If odours (interior air quality) is your only concern than you have two choices run carbon or exhaust the odor. If you are going to exhaust, then you will benefit from an HRV during the winter but likely not in the summer as you'd probably have to run it in bypass.

If humidity is your only concern, get a dehumidifier for the summer use, and check if mosture is even a concern during winter. Unless you are getting condensation or frosting inside your windows or walls (usually occurs at RH greater than 25-30%) you don't have to run the dehumidifer during winter.

Hope this helps

Reggie