Pre-charge UFH in mornings using rules


I would like to create a rule to pre-charge my downstairs UFH in the morning before we wake up.
I am hoping for some comments regarding my proposal & if I am missing anything obvious.
I have been reading through the forums and think I have enough information to make a start.
The Tado thermostats are already integrated into my OH & I can read/set room temperatures.

  1. At 6 am, read and store the current temperature of all downstairs thermostats (Tado)
  2. Turn on all thermostats to elevated temperature (say 25C) like a boost mode
  3. Poll room temperatures every 15 minutes (or equivalent)
  4. When an individual room thermostat has increased by 1C from the initial reading, switch off that thermostat
  5. Once all thermostats have increased by 1C, finish

For the above, I need to capture the initial reading from each thermostat in a variable and then compare it with that each time I poll the thermostat.
Is there anything obvious I need to look out for with the above scenario?

Note - rooms are not cold, but my family likes the feeling of warm floors for bare feet in the mornings.


I am doing the same with my UFH for the same reason. I don’t have thermostats, just on/off valves on OH-controlled switches but as you say your thermostats are integrated just increase their target temperature. They should open themselves.
Note you don’t really want the room temps to increase, just have the feeling of a warm floor. Room temp therefore is a bad indicator. I would use a timer or cron entry to reset target temperatures to normal. You need to experiment a bit how fast after turning off the floor gets colder again to find out out how long the interval needs to be.

It’s even a clever means to save energy: on workdays (when you leave the house anyway after an hour or so) I am warming the floor only of those rooms that we use in the morning (bath, kitchen) but keep my target temperatures on night level until we return from work in the evening.

You can even combine that with presence detection: I start warming my wife’s room floor when she’s leaving her workplace.
Warm feet, happy wife. Happy wife, happy life (her words).

Hi Markus,
My only issue is that my heat pump is running independently of the UFH zones.
My bathrooms are open zones that act as a buffer, so heat pump comes on/off as per the buffer requirements.
To preserve the lifespan of the compressor (Nilan Compact P GEO6) there is a minimum off-time (I think 45 minutes by default) so I don’t believe that I can simply use a delay, hence the heating of the room by 1C.
Other than that, I am in complete agreement with you.

Warm feet, happy wife. Happy wife, happy life (her words).

EDIT: I could always poll the compressor status first - if it is not on, then wait for it to come on then just run with some time delay…

I don’t see what heatpump run times have to do with it. Usually there’s the pumps into the flooring to work independent of the heat creation cycle. A smallish buffer of pre-warmed water is usually enough to get the floor warm (remember you don’t want to heat the room), all you need is to open the valves (have the thermostats open them) and ensure the pumps come on.
How to ensure that depends on your local hydraulic setup and Tado integration.
If you leave control over with the HVAC guys they will tell you to run (and implement) without any buffers to be “more efficient”.
That in most installations results more or less in heat pump run times = pump times but it’s ultimately just a control settings thing. That efficiency claim is big time nonsense anyway, and counterproductive.

I think my concern is that there may not be enough warm water in the buffer zones to sufficiently warm the other downstairs zones.
Depending on whether or not the heat pump is on when I open all the zones, the rooms will get more or less heat.
I’m probably worrying about nothing here - any sort of warmish water should be sufficient to heat the floors to make them warm underfoot.

Yes. And you can deliberately set the interval of that: the smaller the more heat is left for the rest.
Just experiment.

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