Best way to seal gaps in sliding window?

Question

Summer is coming and I live in an apartment where the window can slide up to insert an AC.

Unfortunately, after some time I get bugs and mosquitos coming through the gaps around the AC and at the top of the sliding window (since it is only sealed when it's completely closed).

I tried to use caulk tape, but it wasn't very effective. There'd still be tiny gaps here and there that things found a way through.

I'm now thinking that there must be some kind of foam spray that can do a better job of sealing off gaps. Is there anything like this that is non-toxic and easily removable? TIA

Answer 1

Spray foam would be excellent. Until it's time to take the AC out of the window and you're left with a disastrous mess of sticky foam that you can't scrape off to get the window to seal again.

Get some pieces of foam rubber and cut them to fill in the gaps between the sashes where they don't seal because the window's open. You could use pipe insulation, pool noodles, or packing foam that came with some product you ordered in the past.

You may not have a perfect seal and may have to deal with a few insects that get through, but that's better than a hot, humid room. To be fair, though, I used to do this when we put a window AC unit in an upstairs window, but were able to seal it up well enough (with old, rickety, leaky wooden single-pane windows) that insects weren't a problem. Considering that we live in the Midwestern US where summer bugs can be a considerable issue, it worked pretty darn well for us.