ERV in basement or attic?
Hello,
We live in Georgia, and are having an erv installed soon. Our home has an air sealed attic with open cell foam. We had planned on putting the erv up in the attic to serve the floor below(2nd floor) the proposed instal would exhaust the attic and put fresh air into the hvac to deliver it to the rooms on the second floor.
unfortunately our roof is all hip walls, all walls at an angle and the contractor is saying the air would be pulling off the shingles and it would be dirty air.
solution was to put the erv in The basement and that would add fresh air and exhaust the basement and first floor. He says the fresh air will make it up to the second floor as well…
also we have two hvacs in the basement for basement and first floor and one in attic for second floor.
I like the idea of the erv in attic to give fresh air on the second floor since we sleep up there. I also liked the idea of pulling out some of the attic stale air.
my question is, would putting the erv in the basement deliver enough fresh air up to the second floor? What would be my best option here?
thank you in advance
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Replies
None of this makes sense to me as a good installation approach. Best practice is to use completely separate ducting systems, not to combine it with the heating/cooling distribution ducts. And more importantly, it should be pulling air from outside, via a duct and exterior vent put in for that purpose, not pulling air from the space it's in.
Frankly, it sounds like your contractor is utterly clueless and you should find someone new to work with.
You are most likely to have closed doors in the bedrooms, so you would want the fresh air there. There is also a benefit of taking the stale air pickup from the attic as it brings in conditioned house air into the space (there should be a small transfer grill from the hallway to the attic) and also exhaust any smells that might come off the spray foam.
It would be more invasive, but I would also run a fresh air feed to the main living space on the first floor. Depending on the layout of the house, you can usually do this with two 3" semi rigid aluminum ducts inside an interior wall.
As for the roof vent issue, there is absolutely no reason to not use soffit vents for the ERV. If you don't have big enough overhangs, you can also use a taller intake on the roof .
If you are pulling in fresh air near ground level, your ERV will have to be cleaned more often to remove dust and bugs. Getting the intake up high is definitely better.
If you are in the metro-Atlanta area, consider contacting Sam Young at Home InSight ([email protected], 404-915-5321). He understand how to implement these systems (unlike your clueless contractor).