Program heating settings for nighttime

Just very briefly from on the go, will respond more extensively and with a photo over the weekend:

Tenant asks if it is not possible to split one circuit into two heating circuits?

I find different opinions on this. Read several times that it is "quite difficult," better to have it read by Techem or such tubes.

But I also found entries that sounded as if it were technically easy to implement? I haven't read anything about a cost point anywhere?

Yes, of course it is possible, however, you will also need a separate arrangement for that.

So, two new rule systems? :)

No, usually one controller and two room thermostats are enough. So however you look at it, you cannot avoid controlling your existing system.

And how do the lines then know that now two circuits are supposed to exist?

Which lines do you mean?