K9 Owned wrote:
LOL - Kate will figure it out. A dog door is great. I'd love to have one but it would have to be so big we'd never keep the house heated without going broke.

You might be surprised how a big dog can squeeze thru a little doggie door.
When I lived in Phoenix in the 1990s I had a Miniature Schnauzer and a Pomeranian and a similar doggie door like this one that fits on an existing sliding door.
http://www.youtube.com/watch?v=Y-QtYYZrB1w
A friend of mine went on vacation and while she was away her Rottweiler/GSD mix and Doberman stayed with us. After a couple of hours at my house they saw one of my little dogs go through the doggie door and the big dogs were right behind her. It was a little door made for a 20lb dog but they soon learned they could easily fit through. It was shocking how easily they fit through.
You live in Canada and have bitter cold winters so a dog door of any size is not a good idea to save on heating bills. But it worked well in AZ where we only had freezing temps a few days a year.