North Carolina Fan filter advice

Discussion in 'Maintenance and Troubleshooting' started by frankpc, Mar 17, 2015.

  1. frankpc

    frankpc New Member

    Seeking some advice around fan filters. We have two Climatemaster two stage units - a two ton and a three ton. Both have the MRV 11 rated 2" pleated filters that slide in the air handlers which I replace regularly. My question is - what is the best practice for the 1" existing return air filter grills in the house that the previous air to air heat pumps used? The three ton unit is served by a 20x25 grill and the two ton by a 16x20 and a 14x14.
    Our installer recommended a plain fiberglass filter in each existing air return to catch larger particles and minimize the additional load of having filters in series (ECM fans in both units should adjust at a cost of slight energy penalty).
    I must admit that "stocking" five different HVAC filters is a bit of a pain and getting fiberglass filters is also becoming problematic as most move to a pleated design. That is balanced a bit by easier access to the 1" filter grills and the potential to increase the life of the relatively more expensive 2" filters by "prefiltering".
    Is it best to continue to prefilter with the 1" filters? Or toss them completely and let the 2" filters work as designed?
    While I understand that a visual test can be misleading, it currently takes almost six months to get any visual dust on the 1" prefilters . The 2" filters always look almost new after six months.


    Thanks !


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