On Aug 3, 10:50*pm, Sam Takoy wrote:
Hi,

I want to put a HEPA filter in my A/C Air Return Grille. I check local
big box stores and didn't find anything. Strike-out at local A/C
suppliers such as Michael.

I did a google search "HEPA Air Return Filters" and got essentially
nothing. Some sponsored links were promising, but I wasn't able find
anything there either.

Is this not a commonly available type of filters? Are they not
recommended for some reason? Can someone recommend *an (online) place to
purchase them?

Thanks!

Sam

Most residential air handlers are not designed to be used with any
filter that restricts the air flow more than the cheap one dollar
filter. Restricting the air flow could cause the evaporator to freeze
creating a vicious cycle of further restriction of the air flow.
Lately it has become a good money making gimmick for the hardware
stores to sell expensive air filters to the uninformed. If you insists
on using any other type of filer first make sure that there is some
way that you can observe the evaporator. Is there some kind of access
cover that you can remove to make sure it isn’t freezing? If so then
check it every few hours. If it freezes it will look like one of those
old refrigerators that you had to manually defrost. If it doesn’t
freeze then you’re ok.