ᐅ Underfloor Heating with Individual Room Control—Is It Really That Bad?

Hello everyone,

We are planning a semi-detached house with two full floors plus a basement, equipped with an air-to-water heat pump and underfloor heating, no KfW funding, solid construction, located in Middle Franconia/Bavaria.
Heated areas are:
Basement: a hobby room of about 38 m² (409 sq ft)
Ground floor: guest room – living/dining/kitchen – hallway – bathroom with toilet, about 80 m² (861 sq ft)
Upper floor: 1 child’s room – 1 office – 1 bedroom – bathroom, about 80 m² (861 sq ft)

The heating system is planned with individual room control using thermostats for the underfloor heating.
I have read that this is not ideal due to supply temperatures and other factors.
However, I see some advantages: for example, we would sometimes turn off the bedrooms/children’s rooms (they usually prefer cooler temperatures for sleeping), and the basement is not always needed.
Is this a bad approach? Would it make more sense to group some rooms together (e.g., separate zones for basement, upper floor, and ground floor)?

Thanks for your advice!

Best regards,
NilsHolgersson

No, ERRs are not bad. But it’s better without them.

Here are a few (general and partly simplified) points:
- In a new building, you won’t really have significantly different temperatures (2–3°C (4–5°F) is the maximum).
- Turning the heating off briefly means the temperature will only slightly drop after 4–8 hours. Turning it on works the opposite way. If the heating water runs through the circuits at 28°C (82°F), don’t expect immediate miracles. And if you turn off, for example, your refrigerator (a good example of a well-insulated house), it takes a long time for the temperature to rise.
- Grouping rooms together? No, the more circuits over laid meters you have, the better.
- Omitting ERR requires a separate approval. You are not allowed to do that officially without permission (see building energy regulations / building codes).
- A room-by-room heat load calculation must be done. Please include your preferences – for example, living room preferably 22.5°C (72.5°F), bathroom 24°C (75°F), bedroom 20°C (68°F). The heating system will be designed and calculated based on this plan and with the lowest possible supply temperature for the underfloor heating.
- Understanding how ERR works: Compare it to a car. ERR = brake. Heat pump = engine. Your car won’t run efficiently if you floor the gas but control your speed by constantly pressing the brake. Better to drive evenly. It’s the same with the heat pump. With ERR, you switch a room completely on or off. There is only on/off. So it’s better to plan and adjust well (= hydraulic balancing). Then in winter, fine-tune if necessary and just let the heating system do its job.

Any questions? Don’t hesitate to ask ;-)