Furnace Filters
 

OK I need some help from the brain trust. My furnace filter is one of the washable - reusable types that was in the furnace when we moved in 12 years ago. I wash it out regularly and it catches a lot of crud but I want something better. I know how to use a tape measure. That filter is 20.5 x 30 inches plus or minus a 32nd of an inch. There are lots 20 x 30 filters on the market. I can't find anything that is 20.5 x 30.

What am I missing? Will a 20 x 30 filter work with a 1/4 inch gap on each side?

Is it an electrostatic, or just a giant panel filter? How thick is it?

I would think a couple of strips of styrofoam in there to seal it up would make it fit the 20x30s just fine. You don't really want gaps as it'll let a lot of unfiltered air around the sides into the blower.

The current filter is electrostatic. It is just one inch thick. I was thinking of gluing a 1/4 inch dowel on each side or maybe a 1/2 inch dowel on just one side of the slot for the filter.

Yeah, something like that would be easy and should work fine.

The electrostatics really do work pretty well if they are kept clean and the prefilters are clear, but a panel filter would catch more.

What's the current electrostatic? I tend to mostly see the Honeywells around here.

I think the problem with that is that a panel filter in order to flow enough air is usually 3-4" think and pleated (think car air filter). The 1" stuff I tend to see is the loose fiberglass sort of thing that I don't think would really catch as much as the electrostatic would in most cases.

I just had a new system put in a few weeks ago and got a hybrid, but the space it takes up would require some work on the ducting I'm sure, as it's huge.