we have a doggy door too .. Gonzo loves his backyard, and stays out all morning and usually goes out after 5. his favorite thing is to go out and get all wet in his baby pool, then come running inside and jump on the couch! during the day when its really hot, he prefers to come in and bother everyone trying to get them to play or sleep on the nice cool hardwood floor. he always sleeps inside, on his pillow in my room or in my little sisters room on her bed.