Well, Keystone states "4 season living," and ours is certainly better than any previous RV we've owned, but I seriously doubt deep-freeze winters would be very comfortable. Nothing in the Keystone literature says FT invalidates your warranty. It has no problem cooling in near 100 degree and high humidity conditions in FL. The front LR stays cool. Take a look at the lack of storage if you're considering FT. We knew up front but we pack fairly light and it hasn't been a problem although I don't consider us true full-timers. There are higher quality makes for FT, but you'll pay a high price for one.
