Here's what happened to me: Last Sunday morning, it got really cold, so, for the first time this year, I turned my heat on. Not fifteen minutes had passed before I smelled this AWFUL smell, like burning hair, and my smoke alarm went off. :-( Now, to explain a bit, I live in a fairly new trailer, which I got in June 2014, and, all last winter, I didn't have any trouble with rats or mice. But, for a few weeks prior to turning the heat on, I had been hearing sounds like mice or rats scratching around in the ductwork. Still, I didn't really worry about it, since I had had mice in the ductwork of my old trailer, which I had from 1993-2014 every single winter, and none of them had ever caught fire. They would just run around like crazy, when it would first kick on, and then, I would assume, they simply got the hell out of Dodge, and waited for it to kick off again, before they would get back up in there. Whenever I would actually see them INSIDE the trailer, I would set traps for them, and dispose of them, of course. But, as for them being up in the ductwork, I just figured "Out of sight, out of mind", and didn't really worry about it. I had heard quite a bit about mice and rats chewing on the electrical wires inside the walls of trailers, and causing them to catch fire in the winter, when the heat would kick on. So, needless to say, when that one caught fire, it scared the hell out of me, and I immediately turned the heat off, not wanting to run the risk of my trailer burning down, particularly with me in it. ;-( So, yesterday, I put some poison traps down under the trailer, but, the whole time, I kept thinking: "What if they eat this and crawl off back into the ductwork and die?" "How will I ever get them out then?" :-/ I realize now that it was the wrong thing to do, and will take them out, and use snap traps in the vents instead. But I guess I was just wondering whether anybody else had had the same experience, with one actually catching fire like that, and the smoke alarm going off? You'd think mice would have better sense than to just hang around and let themselves get singed like that, unless it was actually STUCK in there and COULDN'T get out? That's the possibility that worries the hell out of me. :-( Do they ever go up there and then get stuck?

Thanks so much for taking time out to help and for reading such a wordy post! I'll try to get a photo posted. This is a 2 story dutch colonial house. This is a supplied air duct that is metal and is 10 inches in height. It ENDS in the shared wall to the dining room! The register in the kitchen in centered over the window which is over the sink base. I believe this is attic space above both rooms and I think I can read your mind already if you are thinking about relocating the duct? Don't know if DH is up to that project! I've thought about using 12 inch wide accent cabinets on left and right wall ending with a faux door in the corner. The reason being that dust is a huge problem and I don't want to leave top of cabinets bare to ceiling. The other option is to go with bead board with crown molding? But still leaves the issue with building a decorative framing around the duct and maybe using a trio type pendant lights that come mounted on a ceiling plate to mount underneath the duct framework. This stupid duct is an issue in the living room where it ends center of wall! What a joke! Thanks!

Klem, I assume that the OP is thinking about ducted models. OP, you could use jump ducts in the walls to move air from room to room. I think, however, that is not necessary. It might be possible to install the minimally ducted units with supplies and returns for both rooms above the closet indicated. (I don't know how big those units are.) If there is not enough space to do it that way, you can box out a space under the current ceiling next to the wall for the supply or return. I'd likely run them out the exterior walls. Be creative and make them look like they belong. Is the basement finished? If not, maybe the main units could go there. Keep in mind that there is filter access to be considered.

Try finding an HVAC contractor who will do something other than roll his or her eyes, either in your presence or later, when you complain that you can't cool a room to 65 degrees. Why might that be? They'll probably suggest a mini split and be happy to sell you the project, whether needed or not. "studies consistently show ....." My life experiences consistently show that people who think they know more than the experts they hire and have an attitude of entitlement for what they think they should have, sleep less well and are much less happy in their lives than people whose expectations are more reasonable, less self-possessed and more easily achieved. If your son likes sleeping in a cold room, there are plenty of places with a cold climate he can move to. Or, set a good example for him as a father who teaches life skills, suggest he get his own home and work it out himself.