Said It Here

Maintenance installed an AC filter that is too small

An ill-fitting or incorrectly sized replacement air filter can leave gaps, potentially causing throat irritation for apartment residents. It can also raise safety worries about whether the improper fit might cause a fire or damage the system.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    putting the slightly mis-sized filter in at an angle
  2. 2
    forcing the filter to fit as long as the door goes back on

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/hvacadvice2 people · September 2026

In getting a replacement filter this year I realized only once I was going to put this in that it was an inch wider than our previous filters.source ↗

I just don't want to cause a fire in the house or any big trouble like that.source ↗

A couple of the paper pieces did break is that also going to be a problem?source ↗

wanda-maximoff · r/hvacadvice · 9 upvotes

Hello, maintenance just replaced our AC filter and both people living in the apartment are having throat irritation. Not sure if this could be causing it, but it seems like the filter replacement is too small. Is it too small?source ↗

averyweezer · r/hvacadvice · 2 upvotes

Thank you for this I was stressed because this was always the kind of filter we put in it 😭source ↗

wanda-maximoff · r/hvacadvice · 1 upvotes

Where this came up

People with this problem also raised