On Thursday, September 12, 2019 at 8:03:24 AM UTC-4, wrote:
A quick search shows most 18,000 BTU window air conditioners are in the
$600 range- not the $1600 you mentioned.

For $600, I'd pop for a new one as it will likrly cost you a good couple
of hundred buck to get that 20 year old one repaired. Also, new ones are
much more efficient and use a lot less electricity

It's through the wall. Those are the expensive ones. I also need to find one to fit the existing opening (27 3/8" by 17 15/16") Frederich makes several units that have these dimensions. So anything I would save on a smaller unit would be offset by the cost of changing the size of the opening.


Some important factors:

1 - How much is it used, how much does the electric cost to run it?
Like others have said, a new one will likely use substantially less
energy, maybe even 50% less.

2 - Do you have the skills to replace a relay or control board yourself?
What does the part cost? Are parts available?

3 - Any other issues with it, eg a higher or lower output one would be
better, it's noisy, etc?


If the electric bills aren't too bad, a new one really costs $1600 and
you can do the repair yourself, probably better to fix it.