Air-to-water heat pump - Nest Thermostat

Thank you Mycraft for your good summary! My husband grudgingly acknowledges it. But now a slightly strange question: These ERR must be installed (our contractor says it is unfortunately mandatory). Now my husband absolutely does not want to have these ugly parts in every room and asks whether any random room thermostat (flush-mounted) can be installed, or if it has to be from the heating manufacturer's series. The circuits for such room thermostats are all identical, if I understand correctly.

If it turns out that ERR doesn't make sense for your construction project (preferably have it double-checked by a professional), then you can also get an exemption. Otherwise, there are also semi-recessed solutions that don't look as bad anymore. The question is, which builder quotes which prices, or can you choose freely?

You can safely take the simplest version offered to you. Because if the electrician can't connect it and you lose the warranty as a result, that would be saving in the wrong place...

But with a properly adjusted heating system, you shouldn't need to operate those things ever again... the simplest option is just like I did, have them removed and have the builder deduct the RTRs.

How can one get freed? My husband doesn't want to have these simple things hanging on the wall :/

Just type "Befreiungsantrag ERR" into the search engine and you will find it... Links are not allowed anyway.

But that only works if you actually have no room that you really only heat about once a month, right? We have a basement room that is supposed to become a guest room and office at some point. But it is not needed yet because we still have two rooms upstairs that will first serve as an office and guest room. What do you do then?

And later, the room might be used maybe every two weeks and not continuously. The rest of the basement rooms, except for the hallway which is our entrance area, are unheated.