Good Wall Vent Hood Options for ERV?
alex_coe
| Posted in General Questions on
Looking online there are so many options, with some likely more gear toward dryer venting than a good ERV install.
This is one unit I checked out at HD: https://www.homedepot.ca/product/imperial-6-in-premium-wall-exhaust-intake-hood-with-screen-white/1000110479
What type of hoods/vents are you guys using or recommending for 6″ outdoor air penetrations?
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I use those regularly with good results
I used a couple of Broan #641 wall vents and just removed the damper. $55 online, but found them for $30 at my local building store.
I feel like much of what I've seen so far has been underwhelming for ERV use, and most designed to be used for range hood exhaust. Given that I'm only running 6" duct (100CFM Panasonic Intelli-Balance) maybe I should upsize the wall vent to 8"?
What about bug screen on the intake? It seems like it would be wise to fasten some aluminum or fiberglass insect screen to the opening would be a good idea to keep bugs from getting into the system. Then again, I wonder about the impact of this on a 6" vent. A vent with a larger flared opening to allow for a larger piece of screen to be used could be good, or maybe just an 8" vent.
One angle could be an upsized vent connected to a wall mounted filter box on the other side of the wall.
It would be nice to see more videos / articles on this stuff as well as filter box solutions for ERVs.
After looking more closely at some of these it seems the Broan 641/647/843BL are the ones best designed for maximum airflow and largest screen area. I'll be swapping the screen for insect screen on the intake, so the larger area is needed to compensate for the airflow resistance.
I have only installed Zehnder ERV's. Their intake/exhaust wall vent is more like a stainless gable vent. Therefore when I built one for my house and wanted it to be wood it looks more like a traditional gable vent. I asked the building science guy at Zehnder about the screen and he said even changing from their 1/4" mesh to an 1/8" mesh would be a reduction in air flow so I upsized by about 20%. I am in California and fire code calls for 1/8" mesh.
I would be very curious to know a more mathematical real answer to the size of the mesh and airflow. Does anyone have a source for this?
How has it performed? Do you have a link to the vent you used? How many CFM are you putting through it?
Really good to have a larger screen area for less restriction. I was considering just using the standard 1/4" mesh on the outside then having a filter box on the other side of the wall where i could use a larger screen, but I think the Broan 641 provides enough screen area for an Intelli-Balance 100.
I wouldn't use a fine mesh like mosquito screen. The air velocity is too high and dust will clog it in no time from pollen. I have tried using one of those round soffit vent screens (abou 1/8" mesh) as an ERV stale air pickup grill and it lasts about 1 month before clogging.