ᐅ Underfloor Heating Control

In my experience, it is definitely possible to create significant and noticeable temperature differences between rooms, including with underfloor heating. In our current house, which is not very well insulated, we have 14-15°C (57-59°F) in the bedroom and 25°C (77°F) and 21°C (70°F) in the adjacent rooms (bathroom, children's room).

If this were not possible, it would mean a considerable loss of quality of life for me, as I cannot sleep at all at 20°C (68°F).

It also does not make sense to me why there should be a difference in this matter between underfloor heating and conventional radiators. Thermal inertia is not an argument when the underfloor heating in the bedroom is ALWAYS set to 14°C (57°F) (or "off").

The insulation between rooms is certainly weaker than the insulation of the exterior wall, but the temperature differences are also roughly an order of magnitude smaller. However, the insulation is NOT an order of magnitude worse if you build, for example, with aerated concrete, clay blocks, or timber frame construction with mineral wool. The thermal transmission through the door naturally depends on the type of interior door, but a hollow core door probably does not insulate an order of magnitude worse than a similarly sized window in an exterior wall, just to put this into perspective again.

I do not think that the supply temperature is raised when only one room is being heated. The difference between supply and return temperature initially becomes smaller when only one floor heating circuit is "flowed." Of course, this depends on the type of control system; I am not sure if every heating system today can regulate flow rate via pump speed AND supply temperature. Even if the supply temperature had to be raised slightly (which I doubt), but the flow rate decreases significantly (because fewer sub-loops are being supplied and the pressure loss increases, or because the pump speed is throttled), then significantly less energy is transported. This effect certainly compensates for any disadvantages that might arise from the heating device operating at a less favorable point (which still needs to be proven).

Knallkörper schrieb:
because I can’t sleep at all at 20°C (68°F).

Many people like to sleep in a cool room, which I find interesting. (Aside from the fact that you probably won’t stay awake for months during the summer. And people also sleep in southern countries, even during the afternoon in Spain ). People often perceive cool air as fresher, which is why they want to keep the bedroom cooler. However, what really matters for good sleep is not the temperature but the air quality in terms of CO2 and humidity (excluding pollutants). And that brings us to controlled mechanical ventilation or an open window. Neither of these is related to the sleeping temperature.

Oh, and then there is the duvet rule. It’s common in new buildings to use just a summer duvet all year round, which isn’t bad either.

On the topic: Isn’t the valve that regulates the flow rate sufficient according to the energy saving regulations, allowing you to legally skip the control knob on the wall? Assumption: This valve is always part of a radiant floor heating system; one valve per circuit, at least one circuit per room.

So, we have a MAXIMUM temperature difference of 2°C (3.6°F)... we can twist and turn however we like.

Bieber0815 schrieb:
However, the temperature is not what matters for good sleep

Well, with all due respect to your explanation, I know better what is relevant for me. Of course, I can also sleep at 30°C (86°F), but not as well. I also have air conditioning. The air is always fresh because our window is open for at least 2 hours before going to bed, and our bedroom is also very large and high.

Knallkörper schrieb:
If that were not possible, it would significantly reduce my quality of life, since I can’t sleep at all at 20°C (68°F).

That is a matter of getting used to; see Bieber for details.

It should be clear that with an open window and the right outside temperature, you can lower the room temperature. However, your heating system will try its best to keep all rooms within the thermal envelope at the same temperature. Insulation between rooms can only limit this to some extent.

Look up the insulation values for exterior walls, interior walls, doors, and windows, for example by searching for U-values online. Calculate the heat transfer based on your room geometries and so on—that is somewhat more reliable than relying on your feeling that the difference shouldn’t be that big.

Otherwise, common sense should tell you that an interior door, which is about 4 cm (1.5 inches) thick, is not used by chance only as an interior door and not as an insulating exterior wall, which today is roughly 10 times thicker. Also, at least in our case, the glass panels in interior doors are single-glazed, not triple-glazed like exterior windows.

Knallkörper schrieb:
since the window is always open for at least 2 hours before going to bed

During the heating season, you are basically throwing money out the window this way. You can do it, of course, it’s your choice.