Air recovery for direct vent setups

M

Mike D

New member
I can't seem to find anything on this topic here in the forum, so I'm starting a new post. Please feel free to point me in the direction of an existing post.

How do you deal with the negative pressure if you're direct venting instead of using filters? My new place is going to be sealed up tight, and I don't think my HRV is gonna be able to pull in 1400CFM. Maybe I'm wrong.

Do all the direct vent people just have really drafty shops? My shop is in southern Ontario, so there aren't many months where I'm not running either the furnace or the AC. I am planning on running with filters for that reason, but direct venting seems better from an air quality perspective.

Thanks
 
Mike, the dust collector will be pulling air from somewhere to match the volume of air being blown out of your shop. If you are running a conventionally vented oil or natural gas burning furnace, be very aware that you will be creating a negative air pressure environment that has a very real likelihood of pulling exhaust from the furnace back down the flue and into your shop. This exhaust has a high concentration of carbon monoxide which is odorless and deadly. Direct venting is a great solution from an air quality standpoint vs. filters, but you have to allow for replacement air to come into the shop from some place.
 
Rushton said:
Mike, the dust collector will be pulling air from somewhere to match the volume of air being blown out of your shop. If you are running a conventionally vented oil or natural gas burning furnace, be very aware that you will be creating a negative air pressure environment that has a very real likelihood of pulling exhaust from the furnace back down the flue and into your shop. This exhaust has a high concentration of carbon monoxide which is odorless and deadly. Direct venting is a great solution from an air quality standpoint vs. filters, but you have to allow for replacement air to come into the shop from some place.
Click to expand...

Yeah, that's what I'm curious about. Has anyone actually set up a direct vent system,and if so, what did you do to counter the air being pushed out?
 
Mike,
I have not seen anything beyond an open door or some sort of opening. I have not seen anyone on the forum using a heat exchanger. Rushton is right on the potential for carbon monoxide poisoning, especially in tight construction.
Bababrown
 
My basement shop is in Ottawa, Ontario. I rejected the exterior exhaust method as a non-option for this part of the world. As it turned out, zero regrets. The Wynn nano filters work extraordinarily well, and the exhaust from those back into the shop is as clean (or often more clean) as the shop air that was originally sucked into them. Running the D/C is an amazingly rapid way to clean the shop air! Also expensive (electricity) , so I use a 20" box fan with a near-HEPA grade filter setup for that purpose.
 
Thanks Mark.

I actually grew up in Nepean, and my sister still lives in Ottawa too. I would not want that air coming in at -20C and 1400cfm in January.
 
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