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Adding an external filter to ERV exhaust intake: worth the effort?

user-5296010 | Posted in General Questions on

I read an article where it was suggested to add inline filters externally to the HRV/ERV on both the fresh air intake and the exhaust intake. I see less value doing this on the fresh air intake since units already have a filter there, but it might make sense to pick up dust, etc from the exhaust air prior to it passing through the unit to go outside. Would love to hear folks thoughts and experience with this!

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  1. charlie_sullivan | | #1

    I think it's good to have some filtration on the exhaust. A zehnder system has simple filters on the exhaust registers, to help keep the tubing clean on the way to the unit, and another filter when that air comes into the unit. The filters on the registers do get dirty.

    Depending on the filter on your supply side, a big, cheap, low pressure drop filter can help keep the potentially expensive main filter clean and you don't need to replace it as often.

  2. user-5296010 | | #2

    @Charlie My apologies for the delayed response; based on your suggestion for filtering the ERV exhaust intake I've decided to use an inline filter for the exhaust, something like this:

    Adding a filter prior to the supply intake to increase the life of the internal filter sounds like a good idea as well but I would be slightly concerned about making sure that the entire drop filter is properly insulated like the rest of the supply line is; that sounds like it might be difficult to achieve. Have you done this in practice and have you had any issues with condensation on the drop filter housing in the winter if it wasn't insulated?

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