Asked on May 10, 2017

What's the best way to put in a furnace filter that has to be folded?

JackNaomie Moore aka baileyanddaisey, Castaic CALjgordon


Our furnace was installed too close to the water heater so the 20" X 25" filter needs to be folded in order to be inserted. Should the sides of the filter be cut then taped, or is it best just to bend the filter and cram it into the furnace slot?
6 answers
  • William
    on May 10, 2017

    A photo would help. I would bend the filter and push it in the slot. It should retain its shape. If you cut and tape it may not retake its form.
  • JOHN
    on May 11, 2017

    If William's idea isn't possible.....TRY this.... not 100% sure it will work.... but take the cardboard border off the filter on the top and bottom (as I am envisioning it), so you would be able to easily slide the corrugated filter in. However, you would probably need to check it as well as replace it more often, because as it would begin to get dirty, the structural integrity would be missing that would normally keep it from "pulling in" toward the motor...

  • Ljgordon
    on May 14, 2017

    You might try to find a washable filter. I think I've seen filters made of something other than paper, metal and cardboard and are bendable.
  • Jack
    on May 14, 2017

    Thanks. I'll look for that kind of filter at Lowes and Home Depot.
  • I would shop for a washable filter, but, how did this happen? Who would install in such a manner? Yikes! I would move one or the other - just from your description, it does not sound like it meets any building code I am aware of - which can void your homeowners policy. Call the utility company, they will come out and inspect for free.
  • Jack
    on May 14, 2017

    House was built in 1970. I don't have any documentation but I suspect an existing furnace was replaced with a larger one, at least physically larger. If so, the furnace placement would be "grandfathered".

    "Yikes" is good.
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