Need a bit of advice/info for first window unit purchase.

I live in a ~1000 sqft older apartment with drafty wooden window frames. Currently I have an 8000 BTU unit I got for free, and have been using for two years. Unfortunately there's only one practical window to put a unit in (two side-sliding Windows and a fire escape don't play well with window units). This unit just doesn't do a good enough job, so I'm looking to upgrade this summer.

Locally, I can get a 12000 or 24000 BTU unit for a good price. It looks as though 18000 BTU unit would be ideal, smack in the middle, but it would actually cost me ~$40 more than either of the other two options.

Questions:

• is it still worth getting a properly sized unit if it costs more money up front?

• will it be a problem to use a unit this large on older windows? I'm not sure if I can install a permanent support since I rent. The 8000 BTU unit was fine without a support.

submitted by /u/Talks_To_Cats
[link] [comments]