HVAC filter doesn't fit well

I have a very frustrating problem that I hope someone here can help me resolve. I have a split system HVAC that requires a filter in the air handler. The filter size is 16X20X1. I noticed that the filter is a bit too small and, when the fan is running, the filter flops up toward the coil. It seems like the metal flaps that hold the filter in place are a little too large for my current size but too small for the next size up. As a result the coil gets very dirty and I’m told that this can shorten the life of the unit.

I purchased one of those permanent, washable filters that was custom made for my unit and it fits perfectly. The problem is that I own two pets that shed a lot and it is nearly impossible to wash out the fur from this filter. I’d like to go back to the disposable filters but am not sure how to solve this problem. One HVAC company told me they could place filter holders on all my intakes at a cost of around $300, plus I will need to change 3 filters instead of just one.

Does anyone know how to solve this problem? Am I better off with a dirty washable filter than a disposable filter that doesn’t stay in place? Is there a way to buy customized disposable filters? Is there a way to keep the filter in place even if it is a little small? Any suggestions are appreciated.

Don’t look for different filters. Modify the bracket that the filter slides into to fit 16x20x1 filters correctly or call a HVAC repairman to come do it.

Do you know if this can be easily done? My HVAC guy didn’t even mention this option so I assumed I would have to change the entire intake assembly.

Is there enough space to put a disposable filter in front of the washable filter? This would snare most of the fur.

It’s weird that 16x20 filters don’t fit right. It’s not like there’s a brand of 16.5 x 20.5 filters out there.

That’s an interesting idea but it won’t work. The washable filter is thicker than the disposable ones and, since it fits the bracket snugly, it doesn’t allow for another filter to be added.

Take the filter out and measure the bracket that holds it. It’s just bending aluminum duct work. Since your’s appears to be slightly too large, see if you can add something that will make the filter fit more snuggly without flopping down.

This. Are there some disposable sticky tabs or something that you could affix to the disposable filters to make them fit tighter? I think some sort of modification to the disposable filters is going to be your cheapest and easiest fix.

You have to ensure that all the air passes through the filter before coil. You could just shim the filter into place with strapping, etc. and use foil tape to seal the gaps.
Alternatively, the disposable filter are paper and cardboard! Buy the larger size and crease or trim the filter so it fitas snugly in place without having to jam it in.

It sounds as if you need to clean up your coils ASAP.

Duct tape? Seriously.

Modify the bracket. It’s not hard.

No, Duct Tape is a misnomer these days.Air Duct Aluminium Foil Tape is the industry standard.

If you can’t modify the bracket (the preferred solution), get a roll of foam rubber about 1-2" square, with sticky tape on one side. Then stick this to one or more side of the filter, to make it fit snugly. Or a cheaper way would be to buy a plain roll of foam rubber and double-sided tape, but that’s a bit more work.

No, but there are some weirdassed filter brackets out there. Mine measures 17.5x22.5. I just use the washable type with the adjustable frame.

You can always try a second HVAC company.

This might work depending on the construction of your air handler. Get some sheet metal strips and pop rivit it to the filter holder to make it the size of the filters.

Also using spacers can work.

I needed a filter in a fan powered box and we were out of stock. The ones in stock were 1 inch short. I tapped a cut piece of cardboard to the filter to fill the space.
If your coil is dirty now you should have it cleaned.

Keep us posted as to what you try.
Also if you can find a filter house you may be able to order special filters, but they will cost more. At work we use a 17 1/4 by 25 7/8 by 1 inch filter. that is not off the shelf.

I think I’ve come up with a rather elegant solution. I used a vacuum cleaner attachment connected to the vacuum hose to remove the fur from my washable filter…something that did not work with a water hose. Now I think I can keep my washable filter instead of rigging something up.

Thanks for all your advice!