Tado do have their own open window detection, but I think it’s based on sudden temp/humidity changes. I did try using it, but it wasn’t very accurate. Using actual door/window sensors makes it fool proof.
I’ve had this automation running for a few days now and it’s brilliant. It’s probably going to drain the batteries in my TRVs a lot faster, but they are rechargable and the cost savings compared to the gas heating make it a no-brainer.
Your PayPal link didn’t work. Looking at the HTML, it looks like it’s just plain text in an anchor tag.