Replacing AC; can a 15k btu go where a 13.5k btu used to be?

[Cheryl_B]

I got a great deal on a used roof AC but after the guy delivered it to me, the sheer size of its footprint has me concerned. Is this not going to work or will it be okay?

[deltabravo]

Yes.

And when you install it, use blue thread lock on the mounting bolts.
Multiple times mine have loosened up and then water leak in under the gasket when it rained.
Other owners have had the same problem.

Video: Threadlock on the A/C bolts.

[wa8yxm]

Cheryl_B wrote:
I got a great deal on a used roof AC but after the guy delivered it to me, the sheer size of its footprint has me concerned. Is this not going to work or will it be okay?

Short answer YES.

They both fit on a 14" square hole in the roof
The larger one may have a larger box over the hole
But the hole is the exact same size.

[Cheryl_B]

Thank God! I was thinking I made a big boo-boo. Thanks so much. Whew!

[valhalla360]

The mounts/cutout are standard, so no problem.

[ItsyRV]

The rooftop unit may differ in sizes based on manufacture or profile. As ktmrfs said, the roof opening is universal at 14" X 14".

[ktmrfs]

every one I've seen uses the same 14"? square opening on the roof. that's what's important. Even my 9K BTU polar cub uses the same roof opening size.
And they all seem to be designed for a 20A circuit just like the 13.5K BTU

[Cheryl_B]

PS: The rig in my profile is not what I'm currently in. I have to update everything. I'm in a travel trailer now.