Do what he is and easy to use, with some radiators (eg threaded problems) has helped me ...

first of all:
Normally, installation and commissioning are a matter of 5 minutes (if you do not have to think too long about his own switching times and temperatures favorite that comes to). The manual I could well understand, it is in a professional booklet and German.
In our house there are very different old radiator with different threads. Among them are some who have a minimal pitch other than the pre-assembled nuts. The adapter does not help here. The reason is that hardly foreseen all manufacturer-specific variants and can be accounted for by included in the delivery of adapters. But my solution was easy: I pushed with a screwdriver the nut from the controller (here slightly press the flexible plastic tabs inward) - went in a matter of seconds - and then have the nuts of the old heating controllers (old thermostatic valves) away (went as easily) and it pressed on the electronic controller. It broke down anything (ie to make everything undone). If some is here talking of saws that for me simply incomprehensible (the supplied nuts are also metal). Finish and fit.

In a radiator there were problems with the adaptation:
Despite apparently proper adaptation run the radiator valve did not close completely, it was always too hot in the room. Tricks with coin following (to shorten the way) and so did not bring success. The valve was simply too stiff. I then performed the adaptation with some herausgedrehtem regulator and tightened afterwards. The valve closed right now. However, I had to repeat several times (after a few hours, then after a few days) the procedure. Now everything is normal, since the valve through the regular exercise has become normal consistently. Maybe I could simplify my work with some WD40, but when the valves that I no longer have to try. So not the same as the controller suspicious when something does not go, stiff valves may also juggle the controller pretend to be already closed when they are not. We had, incidentally, already with mechanical thermostats, nothing special.

I'll probably order more, we still have plenty of rooms ;-)

PS: I can not (yet) say anything about saving, which is certainly also depend strongly on the individual heating performance.