Recommendation digital heating thermostat

I am still a beginner in this field. But how do I then solve the "problem" that I want 25 degrees in the living room and bathroom, but only 18 in the bedroom? And the 25 degrees in the living room not all day long, but only when I am at home, and also not at night?

Actually, not at all in new buildings. Period.

You simply won’t achieve a 7-degree difference permanently in a new building (apart from that, 25 degrees in the living room is very unusual). The problem with new builds is that everything is thickly and warmly insulated, so temperatures equalize. Just imagine packing hot coffee and ice together in a cooler/thermal box. The temperature outside the box hardly affects the temperature inside. But inside, the coffee temperature and ice temperature adjust – a balance is created. That’s how it works in a new building too. You can have the underfloor heating set to different temperatures (often 22 degrees in the living area, 24 in the bathroom – also just 20 in the bedroom). But you won’t notice big differences. That’s why (electric) supplementary heaters are often installed in the bathroom, so you can “quickly” increase the temperature.

Of course I know that underfloor heating is sluggish. That’s why my thought was to set it to the desired temperature in each room, but already a few hours earlier, and then let it cool down earlier as well.

Of course you can do that. Then the underfloor heating starts full blast at 12 o’clock so it’s hot at 6 pm. But adjoining rooms will also be heated (e.g. the adjacent bedroom, where you then open the window to keep it cooler!?). Then turn it off until the next morning. That’s not good for the heating system or your consumption at all.

An underfloor heating system in a new build is set and then (actually) runs without adjustments.

Thank you for your explanation. So, with the underfloor heating, you don’t lower the temperature at night, like you do with radiators? Isn’t that ineffective? The best solution would be two heating circuits, one for underfloor heating and one for radiators, which you can quickly switch on when needed? But that would surely be too expensive? And what do I do during the transition period, when I currently only heat the living room and hallway with the fireplace (that’s why we are used to 25 degrees)? I would have to turn the heating in the living room to minimum then, as I only want warm feet.

So, you don’t lower the temperature at night with underfloor heating like you do with radiators? Isn’t that ineffective?

On the contrary, that is exactly effective. Even heating load. Here’s an illustrative example. If you constantly floor it in your car and then brake hard, you will have a much higher consumption and wear than if you drive evenly at a moderate speed.

So the best solution would be two heating circuits: one for underfloor heating and one for radiators, which you can switch on quickly when needed? But that would surely be too expensive?

Not necessarily more expensive, but unnecessary and ineffective. Radiators usually require a higher supply temperature than underfloor heating (unless you’re willing to spend 600-800€ per radiator – then there are radiators that operate with really low supply temperatures). So the heating system, e.g. a heat pump, which becomes ineffective at higher temperatures, first heats the heating water up high for the radiators, and for the underfloor heating the hot heating water is mixed again with cold water to achieve the lower supply temperature.

And what do I do in the transition period, in which I have so far only heated the living room and hallway with the fireplace (that’s why we are used to 25 degrees)? Then I would have to turn the heating in the living room down to minimum, as I just want warm feet then.

Free yourself from the thought that you will actually get warm feet. That is no longer the case in new buildings today. In the transition period you might have 27 degrees supply temperature, but you won’t feel that anymore at your feet.
But of course no one stops you from having a fireplace in the house. Great thing and not a bad addition during the transition period.

Free yourself from the thought that you will really get warm feet. That is no longer the case in new buildings today. In the transitional period, you might have 27 degrees flow temperature, but you no longer feel that in your feet.

Honestly? That would be one of the reasons for me to build new at all. I finally want to be able to walk through the house in socks; currently, I always need warm slippers.

Has that changed drastically in the last approximately 10 years? I always have warm feet at acquaintances in a house about 10 years old, which is very pleasant for me.

However, we will have gas heating.

Has this changed significantly in the last approximately 10 years? In acquaintances' roughly 10-year-old house, my feet are always warm, which I find very pleasant.

No, it hasn't changed. However, if you don't necessarily plan efficiently and require a high flow temperature, you can also get really warm feet. With tiles, they also feel warmer compared to parquet, for example. The gas heating system is significantly more robust in terms of design than a heat pump. Which KfW level are you aiming for anyway? And why gas at all?

Even if you use gas, the heating system should be designed for a heat pump so that it can be easily replaced in many years. A heat pump simply operates best with a low flow temperature.