I recently installed the locking cat flap to our basement door, though I don't use the lock. The cats take some getting used to the idea and I think a lock would make them claw at the edges of the thing, which is what they do when they're learning to use it. Anyway it certainly would offer no protection from cold air.

You can get a door with recessed panels if you don't mind the cat flap being centred in just one of the panels, if you get my meaning.

Good luck with your catio!

I get your meaning, but I think the panels I've seen are too narrow for that.

One idea is to wait to install the pet door and just let them in and out manually at first. I may want to see how the cats do in the porch--I don't really want to let them out there unsupervised until I see how secure it is, especially since I'm not at home during the day.

I've had no success with double-flap doors with my cats.

I installed a double-flap dog door (for better insulation) from my family room to the backyard for my dogs, and the cats have NEVER figured it out. They initially pushed through the first flap, but seemed unsure of how to proceed - it was as if they were afraid to get stuck in such a tiny "room". After the first few attempts, they've ignored the double-flap door completely.

I have a single-flap door from my basement out to my backyard, and a single-flap screen door in a bedroom window out to a pergola that the cats climb to come in and out during the warmer months.

All of my cats have had no problems using any of several single-flap door models that I've had over the years. But double-flap doors? Forget about it.

You can use a paneled door but be prepared to use shim/filler or weather stripping in the area where there are gaps. I would center the cat door....... which would place the bottom edge and a portion of the top and side edges on the flat part of the door. The upper left and right corners of the cat door would be over the recessed panels and will need some type of filler and caulking. One tip, be sure to follow the instructions and place the door at the correct height for your cat. You don't want the cat bending it's back every time it goes thru the door.

Of all the cat doors I've seen, even if the flap itself doesn't lock, there is a panel that slides over the cat door to prevent it from being used.
I have a cat door with a single flap that leads out to the enclosed area of the deck and I leave it 'open' year round. Only when there are very windy days do I need to put the solid panel in but otherwise I've had no problems with the tiny amount of air that leaks thru. Occasionally you will need to clean the edges of the door where the magnets are since they will slowly get covered with body oils and soil. When you notice the door isn't staying tightly closed you'll know why. :)

I'll see what doors are available.

I think my cats would be sufficiently motivated to figure out the double flap thing.

I'm mainly concerned because the door is in my bedroom near my bed, so don't want it to be any colder/hotter than it would be without the flap.

I have s raised panels door to the basement in which we cut a cat hole at the bottom (www.cathole.com).
No flap though.

Did someone say 'Double flap'??