ERVs and VOCs
Debra_Ann
| Posted in Mechanicals on
Quick question: One of the advantages of using an HRV or ERV is to exhaust household air that may contain off-gassed VOCs. ERVs exchange both heat and some moisture between the incoming air and exhaust air.
Does it also exchange some of the VOCs, so that the incoming fresh air may contain a portion of the VOCs we are trying to exhaust out of the house? I’m not sure how it could exchange moisture, but not gaseous chemicals.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
I don't know of any data on that. I think the moisture exchange is a two step process--first uptake by the membrane from the moist stream, and then evaporation into the dry stream. The membrane material might not attract VOC as it does moisture.
But an ERV doesn't eliminate moisture exchange--it just reduces it. So worst case, you still get VOC removes, just at perhaps half that rate that you would with an HRV. That's worst case--I guess it's much better than that, but I don't know.
Some discussion in this can be found here:
https://www.greenbuildingadvisor.com/community/forum/mechanicals/36260/ervs-and-formaldehyde
Just a FYI, trees naturally create a lot of VOC's and are for example responsible for the blue hue of the Blue Ridge Mountains.
In any case, iirc filters which contain activated carbon will capture VOC's. HRV/ERV's have filters in them to help keep the exchanger clean. I don't know if any of these filters contain activated carbon or some other substrate which will filter out VOC's. You'd have to contact the manufacturer.
The membrane within a HRV/ERV is not designed to filter VOC.