I had a doghouse built about 20 years ago it had self regulating heat trace that you use to keep pipes from freezing in the floor. I had an underground GFI protected service for it. The doghouse was a 4 by 8 with a 4-½ foot ceiling with a 10/12 roof. It had R12 in the walls and R30 in the attic. I can’t remember the size of the covered front porch. I know it was the width of the doghouse and I guess it was about three-foot deep. My wife couldn’t have children so I had the dog. I miss that dog. I can still see his eyes, how he would look at me when he wanted something.