ᐅ Underfloor heating without a thermostat – but how?

I have often read here that the thermostats are more for decoration than actually used. We currently have underfloor heating as well, but our apartment building is over 20 years old, so I assume the insulation isn’t as effective as it is today. That means we adjust the heating a bit more frequently. However, I can imagine that once it’s properly set up, the heating just runs throughout the winter. But without the thermostats, how does the house determine the current temperature? And how is the underfloor heating controlled at all? Just by the control valves on the heating system? I hope someone can shed some light on this 🙂

A multi-family house means different apartments with individual heating demands, such as gable-end units, middle units, and so on. Be glad to have a setup that allows you to maintain your preferred comfortable temperature.

Bauenaberwie schrieb:

But without the control valves, how does the house determine the current temperature?

The house does not know the indoor temperature at all, only the outdoor temperature.

And through the adjustable heating curve, this temperature is translated by the heating system into the desired supply or return temperature of the underfloor heating.

Bauenaberwie schrieb:

So how is the underfloor heating adjusted at all? Only by the control valves on the heating system?

Yes, by the control valves on the heating system and the resulting flow rate selected in the circuits.

Ok, so basically I control a certain temperature on the radiator, and by adjusting the flow through the heating coils, I regulate the temperature? But what if, unexpectedly, it’s suddenly 15 degrees Celsius (59°F) outside in mid-December? Does the heating system automatically adjust the heating temperature? Or do I have to manually reset it on the radiator each time?

Bauenaberwie schrieb:

But without the controllers, how does the house determine the current temperature? And how is the underfloor heating adjusted at all? Only by the control valves on the heating system? I hope someone can clarify this.

Based on a performed hydraulic balancing calculation, the house determines how much water flows through each room (in the underfloor heating). If this is done correctly and the heating curve is properly adjusted (control based on the outdoor temperature or outdoor temperature sensor), the correct amount of water is always supplied to the room at a given outdoor temperature to achieve, for example, 22°C (72°F) indoor temperature.
So, the house itself doesn’t need to measure the temperature. It is reached automatically by the set system.

That’s the short version. You don’t need to make further adjustments because there is nothing left to adjust. In transitional seasons, the heating might turn on a little too early or too late, but that is manageable.
Of course, it may be necessary to fine-tune individual heating circuits or make small adjustments to the heating curve. But overall, the system then runs independently.

Perfect, thanks for the great explanation. So, we will probably skip the controllers. Thank you very much for that! So, if I’m comfortable with 20 degrees Celsius (68°F) in the bedroom, I just reduce the flow there a bit? But that doesn’t affect the other controlled values?