Concerning heating - do you know what are the optimal settings / system?
I realized that when I set the heating at "3" (the range is "* 1 2 3 4 5" with "5" being open throttle) the radiator is not lukewarm. The bottom part is cold and the top part (where the heat measuring gizmo is neatly located) is hot.
So I suspect that I pay full price no matter how much I open the valve. If my theory is correct the cheapest way to heat would be 5-*-5-*-5- and so on instead of the constant 2 or 3. Does anyone know more about it?
even if it does not seem that way, the 1-2-3-4-5 settings are actually temperature not mass of hot water.
Dont ask me why a 5-system is used, I have asked that question myself a lot of time.
It has to be some sort of a bimetal shutter.
If the temperature rises above one points, then it closes, under the temperature, it opens.
So if you are just around that temperature, it opens and closes shortly after, making the top hot and the hot water cold before it reaches the bottom.
That is to say, normally it shoudl be open long enough that the whole radiator should get hot. You either have an unusual hairsplitting conroller or something is wrong.
When was your radiator last vented? Perhaps you have air in it. Or in the big system, if you share the oven with other people.
In theory it should make no big difference of you use e.g. 3 constantly or 5-0-5-0-5-0
If you do it manually and careful of course, you only switch it on when you really need heat and not just because the temperature fell. You can plan that ahead with the opening windows etc.
So in praxis carfully use the 5-0 method ;)
BUT: More important is the size of the radiator. For example, because of space problems I have only a very small one in the bath, which is a real drawback - it needs at least 10 minutes full power to make the room warm.
On the other hand, in a slighly bigger room, I have a radiator with more space in the middle and better water distribution (better air circulation, better heat transfer) and nearly double the length.
It takes about 2 minutes (on 5) until it is fully hot. Then I set it back to 0. The amount of water/minute is the same (same pipes everywhere) and it is even a bit farther fromt he oven.
BUT it heats up the room more then the 10 minutes in the bath. 1/5 of water (=money) but more warmth.
It amazes me every winter ;) Even at -10°C or less I only had to use it for 2 minutes every 2 hours.
Of course if I forget it and have it on for 10 minutes, I "must" open the window because its so damn hot lol.
tl;dr
the size of romm/radiator is more important then