Bulb Seals will make all the difference
Forgive me if I make a false assumption here, but we made this mistake and thought we would share it. We didnt know anything about it, but maybe you all do.
On the Keystones, the slides dont actually seal against anything on the inside when they are out. Only a plastic channel.. As you can imagine, in AZ/NV last year, our AC ran all the time because heat was slipping past those plastic channels. When we moved to DC last December we had the opposite problem where the furnace ran practically non-stop. We were stuffing kitchen towels and rags in the sides of the slide at the floor level..
Finally in late January when I could take no more, I went back to the dealership (who shall remain nameless) and asked what was going on.. I thought the slides may have been out of adjustment or something.. After about 5 minutes in the shop, the fella came out and asked me why we took the bulb seals out of the trailer.. You can imagine us looking stupid trying to figure out what he was talking about.
Longer story short, the dealership assumed that the trailer came with them, Keystone never puts them on at manufacture time, and we were the dumbasses who lived like that for almost a whole year... For $200 bucks in parts, we lived cold and hot and almost didnt buy this new Montana thinking that Keystone was a crap product..
The funny thing to my wife and I is that both trailers were marketed as 4 season trailers, but neither came with the seals.. amazing!
Get the bulb seals people.. Live comfortably!