Air cleaner filter

[LCHIEN]

I have a Delta air cleaner, the model before they went to the 2-speed one that hangs from the ceiling.

It uses 12x24 filters (or so I thought) and I thought it about time (again) that I replaced the outer filter (standard furnace filter) which prefilters the inner pocket filter.

(see attachment of old vs. new if you don't believe they actually work)

I measured the one I had on there (some original Delta filters)
and it was approx 11.5" x 23.5", I figured this was a standard 12x24 filter.
Turns out the one I bought was 23-5/8 X 11-7/8" and it was about 1/4" too tall to go into the opening. I had to do some fancy work with my swiss army knife and a roll of masking tape to rebuild one side of it and make it fit. Lots of hot melt glue was used in the construction of the original.

So, are these non-standard sized filters in the Delta or did I just get an odd one?

To answer my own question, I must have got an odd one. A quick search on the net finds one furnace filter mfr says his are 3/8" less than the even inch dimension they are sold as, and another mfr. says his are 1/4 to 1/2" smaller than the even inch dimensions given. I think those would fit my Air Cleaner.

[atgcpaul]

My Jet air cleaner filter is also 12x24. I didn't measure the actual size of the
filter, though. My local HD doesn't carry this size, though. I was thinking of
cramming two 12x12s into that space.

[MBG]

I also have the Jet and it does take 12x24 filters. I can find them once in a while at Menards.