The cats love being on the patio – so much so that they get really bitchy when their catio access is cut off.
Usually we keep a window open for them but that’s becoming a less appealing option for us as the temperature drops. The other day I realized a scrap of wood I had leftover from another project was the perfect height for a window insert, so I ordered the cheapest pet door offered on Petco.com ($13.99 PetSafe 2-Way Cat Flap – “Give your pets the freedom they deserve”).
I cut the wood to the correct length using my handsaw and then cut out the pet door hole using a hand-me-down RotoZip saw from my dad.
Victory!
After painting the wood white, I applied foam strips to all four sides. This roll was left in the library after the renovation at MGB; no one ever returned to claim it, so I took it. It’s really useful stuff.
The foam helps the wood stay gripped in the window and makes a tight seal all around.
I can’t believe how well this turned out. And quickly, too.
At first the cats don’t get it.
But treats help!
Project Palermo 
What a fabulous place for the cats. I would love it also.
love your cat’s confused look :D