Apparently, the filter for the unit is missing, and the coils need to be cleaned. There’s no obvious sign of mold/mildew, but Sam says that fresh air is coming into the bedroom via the unit, and our neighbors on that side have been burning something in their backyard.
I found the website for the manufacturer, and of course, the manual for our model isn’t there. The self-service section of the site does mention that the coils need to be cleaned, but doesn’t say how to do it. I suspect that it involves coil cleaner and a hose. Coil cleaner seems to come with a/c service people. I’ll have to ask my father if we can get some and use it safely.
Sam remembers a filter but hasn’t seen it since we moved here, so we may have to order a new one from the company. Of course, their not-helpful site doesn’t have any information about parts, either. So I sent them an e‑mail, and hope that they’ll reply.
They asked me to do a review of my experience with their site. That was probably a mistake, but I did it. Their ratings may have just plummeted.
Now the girl and I need to get to work getting the house ready for our Dragon*Con guest next week. I hope the “guest room” isn’t too hot for him! Maybe I should put up a Freecycle post looking for another window unit?