[MENTION=1904]cali baker[/MENTION], I got a doggy door for my 3 dogs last year and for the most part, I love it because it has eliminated our getting up and down constantly letting someone out and in. Mine has a slat that you can insert and lock, which is what we do when we leave the house or when we want them to stay in for some reason, i.e., the yard mowers are mowing. Winnie doesn't ever stay out long enough to get overheated--all three of my guys stay in most of the time and follow me around.
There are a couple of things I don't like about the doggy door: I never know exactly when my yard mowers are going to show up and I know if the dogs hear them first (which has never happened) they will run out there. Also, sometimes I would like to put the slat in the doggy door to keep them outside for a while, but they run and chase each other in and out so fast that I'm afraid someone will forget the slat is in the door, try to run in at full speed and break their neck!
Overall, I'm glad I got it.