Needed a doggy door for my dog but I didn't want to cut a hole through our garage door. Found this non-permanent solution that claims to be insulated and decided to give it a shot.Pro'sDouble pane tempered glass. Even the doggy door is double paned plastic. Fits well into a 78" height sliding door. Allows you to continue use of your sliding door lock as it comes with its own set of lock catches. This is a well-built insulated doggy insert. Although it was 102 degrees outside, I couldn't feel any heat coming through the doggy door, glass section or the vinyl. The door actually looks fashionable. It makes it look like you have a multi-sectional window instead of a boring slider. The doggy door has a plastic sliding locking panel to allow going on vacation and locking it up.Con'sThe spacers are just a pain to get just right. Found that adjusting the spacers on the hooks to be the toughest part. Even though the instructions say that the section gap needs to be 5/16" minimum, it really MUST BE 5/16"...not anymore and not less. Otherwise, your "H" Section gap is going to be very noticeable and allow the outside air to come right in. Even though I had 5/16" gap, you can still see the outside light coming through on each side of the H (see pics). The "H" Section is not even insulated internally at all. This is the worst designed portion of the whole door. Ideal...re-design it, insulate it and make it to where outside air cannot just pass through. I recommend you caulk all the way around the door...and especially the H section. The slider opening is tight yet usable, but don't expect large people to make it through. Your screen is pretty much useless now. You can't close it without it blocking the doggy door. We ended up removing ours and storing it in the shed so we have a better view outside. Our sliding door does not fit into the door seal extension with the seal extrusions. It has to be crammed in there for the latch to work. Additionally, the outdoor portion of the weather seal on the door is exposed because it simply won't fit. The draft seal they provide stinks in that it will fall off. Just buy a 3M silicone draft seal and use that instead.OK, so what do I think of the door? I think it is the best one out there for vinyl sliding doors. It is a solid door and while it has some issues, I feel I can live with them (or work around them). I watched the installation video 4-5 times prior to opening the box. Note for those putting the door above a raised patio step. I made a ramp leading up to the door...otherwise, it would be a full 12" from the bottom of the doggy door opening to the top of the patio step....which is simply too high for a dog to get into.The door works great for my dog and he is happy that he can go in/out 24x7. I'm happy that it is insulated for Summer/Winter EXCEPT for that H Section. Will report back on reliability as times goes on...