This is indeed a badass wall mounted doggie door. I would recommend it if you are looking for a duel flap wall mounted door that will keep the elements out by far the best door in the market - not a plastic cheapy by any means, this is a full aluminum door with aluminum hallway through the wall. The duel flaps will keep your house insulated so you don't have to worry about that. I live in AZ and today was 110 degrees (fun day to install a door), but after the door was installed I put my hand touching inside flap in the house and it was cool - that is what I got this for.Now you may have heard the installation is not for beginners, I will agree with this. I consider myself a pretty good do it yourself type of guy, that has a fair amount of tools. That being said, it still took me 5-6 hours to install (because I'm a perfectionist). I would suggest if you are considering getting this door, for a large door or the extra large door, to get out your stud finder and look at the locations you are considering FIRST! I have a large door, and the found that the template needs 12.5 inches to be cut out for this, by the luck of god, the place I wanted to install had studs 13 inches apart - now this was a very tight squeeze and I had no room for error when it came to the width - height no problem. That being said this is how my installation went:1) inside hole - basic dry wall - easy peasy, just get your template and use a level on top to make sure it is level. this was a piece of cake, I did go and buy and extra long 3/8th drill bit to go through the dry wall to the outside wall though - so this was +13 bucks for a drill bit I'll only use once.2) outside wall: OMFG, after removing the insulation I found out the out side wall was stucko that was covered over chicken coop wire - WTF? So the tools I had for going through basic dry wall died fast, and was forced to go back to the hardware store and buy reciprocating saw with metal blades that can handle chicken coop wire + 90 bucks, well I got a new toy tool now I guess? crap this is getting expensive... well after that bingo! that cut through that outer wall in no time.3) okay, now it was time to measure the "hallway" the inside wall to the out side wall, and take off 1/4 as the directions say and cut the aluminum appropriately. OMG, this was the hardest part of the entire ordeal. while trying to cut the outside wall with the blade that was in the packaging it dulled to nothing (so I had to get the reciprocating saw), but now I had no blade to cut the aluminum with, in hindsite, don't use this blade for anything else then cutting drywall and the aluminum - use something else for the outside wall! you guessed it, I had to go back to the hardware store and purchase some metal blades for my jigsaw, get the blades that have small and close teeth, the bigger ones will cause the aluminum to "jump" around while cutting and bend it.4) now now it's pretty easy and getting to the home stretch, simply add the top and bottom aluminum pieces like they say and then the sides to the inside door, use the caulking and be liberal with it.5) now take the outside door and get it so it connects with the aluminum "hallway" I did this by myself, but if you have some one else around it would be helpful. After they are are "connected" you'll take the long screws and connect them to all four corners. just do so it is together, not tight as you'll have some play room to make sure it is level after you have it level tighten that bad boy up and boom! it's together! you just no have to go outside and take the protruding screw bit and simply go up and down with it - it will cut itself off at the bit where it is screwed into the door, then simply put in the screw covers and kick your damn dog through the thing (just kidding).This all being said the installation can be tricky, but not impossible, just make sure you have a few hours to kill, and don't rush it, take your time and you'll be fine. I hoped this helped!