Bummer to hear the room is too small...already half way built and $800 in. : ( The room won't be right on top of concrete. We're building it up with a sub floor and insulated walls. Have no idea yet how warm it will get with the heat duct but I'm ready to get a pig blanket or space heater mounted on the wall for supplemental heat. Feeling confused...
You'd be better off using your money to winterize her shed. Put a doggie door in it so she can make up her own mind to go in or out.
If I do not give Bob the choice and I don't open his doggie door for some reason, he throws temper tantrums and rams his doggie door, spreads the hay all over and craps in his water dish. BUT...if I open his door in the middle of a blizzard he'll go out, take one turn around his perimeter and go back in. No hay spreading, no poop in the water dish, it is such a difference. He simply wants to control as much of his life as he can...but I spent almost $1200 winterizing his shed. Floor, roof walls etc. I have a heater in there that keeps his shed at a constant 85 degrees even when it's freezing outside. And that's at the heater's lowest setting. Your situation is workable, just gotta work at it...
Thanks everyone. I had a hard time with the info. at first because I'm so invested in the room that's almost built. I do understand and agree with what everyone had to say though. Her summer shed is a suncast glide top shed...kinda like a rubbermaid. It's not insulated and would be impossible to get that winterized. I am trying to make a last minute change to her garage set up though. The room will be 6'x 7' but I think we could cut out a door in the side of the garage. We would just have to build a 3' long narrowed walkway to the door. I'm sure there won't be many days were she's able to go out but at least if she's really restless she'll have the option to take a quick walk . Last winter was mostly below zero.