I’ve now been and asked for a quote from 3 big box UFH companies in the UK for the planning and design of our heating system. They have all come back with designs with many zones (10+) in some instances, for a home with only 5 habitable rooms!
The house will be a highly efficient SIP with MVHR, heat pump etc, yet even after telling them this, they still insist on designing systems clearly engineered for higher temp boilers.
Does anyone know of a design service that actually understands modern practice of low-temp open-loop heat pump design?
Could you be mistaking loops (usually not more than 100 metres of pipe each ,which can all connect to the same manifold) for zones? I have 5 loops connected to one manifold in a single zone system in a 75m2 bungalow.
No, you’re right to ask, but one quote I received had 11 thermostats! So I can only assume they wanted to control them as separate zones. But yes, I do understand the physical limits of the pipe runs and that 1 zone can have many loops in it!
I had a similar problem in the past. I had a “suppliers design” with 4 thermostats. Your 10 seems over-kill.
My supplier argued it was for better household control, even when it was an open single zone system design. In the end, I had to instruct the supplier to provide a single thermostat in the hallway. The control was at my risk.
I then manually “adjusted” the flow to the rooms via the manifold flow valves in the winter season to better reflect the way the house actually heats up in the day/night. I used mini temperature sensors to check room temperatures during my calibration period. I was able to drop the upstairs bedroom temperatures to ~19C with the other rooms set at 21C. My house is a 2 bedroom plus study.
It’s a compromise and may not be the answer you seek, but it was the only way I was able to manage the situation. You are right to push back on the cooky cutter approach…
Good luck!
Late to this, but in case it helps anyone who lands here with the same problem: I’ve built a browser tool for exactly this kind of self-design. Disclosure, I’m the maker, so weigh it accordingly.
https://underfloorplanner.com: you draw the rooms over your floor plan (PDF or image), place the manifold and enter each room’s heat loss. It lays out the loops (counterflow spiral or double meander, each loop kept under the pipe’s maximum length with the tails included). For an open-loop, single-zone design the useful parts are:
the flow temperature each room needs to meet its heat loss at your pipe spacing, screed and floor covering (EN 1264-2 output), so you can see which room sets the weather-compensation curve instead of adding thermostats
the flow rate for each loop, i.e. the flow-meter setting for each manifold port, which is the balancing Galicia describes doing by hand
floor surface temperature against the comfort limit, and the pressure drop of each loop
One room is free, and whole-house plans are free up to two rooms; the full house is a one-off €39. No account, and plans stay in your browser.
If anyone has a supplier design or a measured floor output to compare it against, I’d like to hear where it disagrees.