House too warm, remote heating controller set to 1

Depending on the heating technology. With an air-to-water heat pump, probably a few % per degree of flow temperature.

For example, we have about 23~24 degrees in the bathroom and 21 to 15 degrees in the other rooms, and yes, the temperatures stay stable when you close the doors.

You can still manage that.
In 2016, I also adjusted my heating according to the warmest rooms (bathroom and living room). Set the ERR and the heating circuits there to full.
Then lowered the heating curve until the rooms reached the optimal temperatures. After that, set the ERR fully open in the other rooms and regulated the flow on the heating circuit distributor down. Finally, removed the unused actuators and closed the corresponding ERR so no power is needed for the actuators anymore (my actuators require power in the "open" position).
Since the beginning of 2017, I only have actuators in the guest room (ERR is only opened when needed) and, as a precaution, in the bedroom.
Since then, it's been running so optimally that I haven't had to adjust the heating curve or the remaining ERR and still always had the desired temperature.

How much do you save percentage-wise by tweaking things?

Unfortunately, I can’t say exactly how much less energy our heating (heat pump with surface collectors) now consumes because I only installed a sub-meter for the heating in October 2016.

All I can say is that according to current estimates, the total electricity consumption (household + heating) will be at least 1000 kWh lower in 2017 than in 2016 and 600 kWh lower than in 2015.
Parts of this reduced consumption could be due to a slightly smaller number of laundry loads and a more efficient dishwasher. On the other hand, a second refrigerator was purchased for the garage.

Lowering the flow temperature by 1 degree saves about 3% energy according to the internet. However, this is combined with the necessary hydraulic balancing, resulting in a gentle mode of operation for the heating system (regardless of which one). Because this reduces cycling (on/off operation). Especially condensing boilers and heat pumps are quite sensitive to this, which can significantly affect their lifespan. Additionally, losses during burner start-up (oil and gas) are the greatest. Standby losses are also reduced.

And now the most important thing: it costs a few hours once for gathering information and then maybe a few hours throughout the heating period. Otherwise, it does not involve any costs. It increases comfort and even saves money. To be honest, I can hardly think of any arguments against it.

Hi everyone,

a little interim report after almost 1 week of "observation" with the following settings on the heating system:

-Max. 35°C design temperature (=flow temperature of the heating curve)
-All RTR set to max. (i.e. on)

With this, I achieve just under 22°C in almost all rooms. Our extension (also connected to the underfloor heating) only reaches just under 20°C.
Last night it was just about 0°C outside and this morning (now at 5:30) about 21°C in the living area.

I will now change 2 things:

-Increase the design temperature to 37°C (so the extension gets a bit warmer)
-Lowering currently programmed from 11pm-6am, will be programmed to 11pm-5am

I will report back!

Best regards, Barossi

Is a reduction even sensible with underfloor heating? I always run a constant temperature without nighttime setback.

I would also keep heating continuously. If the difference remains, you can slightly throttle the other heating circuits. Then you should reach the same temperature in all rooms.