Learning Thermostat advice

LateStarter

Agree that underfloor heating poses it's own challenges. But I have what I have, and need to get the best out of it.
SO it's come down to 2 choices, as I'd rather not fiddle around much with wiring.

• Netatmo (wired) smart thermostat - I'll need 2 of those, and they can be configured per zone
• Drayton WIser Kit 3, which seems a bit cheaper, and is wireless

I'd appreciate any feedback from people who use either of those.

BUFF

I thought that the Netatmo used batteries?

LateStarter

BUFF said:

I thought that the Netatmo used batteries?

It does - the batteries power the thermostat, but the thermostat itself is a wired replacement for the existing wall thermo.

BUFF

afaik it doesn;t have to be though, it can be wireless & put on a table , moved around etc.. But all of these devices if used wirelessly require hardwiring a relay device of some kind into the boiler some way.

The Wiser system most likely will be cheaper especially if you want (& your boiler can handle) OpenTherm.

matelodave

I would have thought that a programmable thermostat would be more appropriate than an expensive all singing and dancing smart stat when trying to control slow response underfloor heating. 

Miser1964

A Drayton Digistat +3RF has served me well for years connected to a combi. However I've just splashed out for a Nest 3rd Generation as the 5+2 programmes on the Drayton was too simplistic for my working patterns and I wanted the ability to set temp remotely via mobile. 

LateStarter

matelodave said:

I would have thought that a programmable thermostat would be more appropriate than an expensive all singing and dancing smart stat when trying to control slow response underfloor heating. 

A programmable (non-learning) thermostat would not be able to turn on the boiler at the appropriate time, such that the room is 19 degrees at 8am, whether it was -5 or +10 outside. You've either got a room that's way too cold, or you're heating the room at 4 am.

chris_n

An underfloor heating system is not going to work efficiently with a combi boiler the way most people use them. Most people use the combi to heat radiators for a couple of hours in the morning and a couple of hours in the evening. This will not work with an underfloor system in a slab regardless of how you try to control it.
The combi will not be able to put water out at a low enough temperature for the floor so would need mixing with return water, the boiler will not be able to modulate down enough and will then switch off. Short cycling like this is very inefficient.  
The system really requires a buffer vessel with it's own pump and control system for the floor. This would allow the boiler to do a long burn to heat the buffer as required by the water temp in the vessel regardless of what is happening in the floor.

70sbudgie

We have a relatively large concrete floor with wet UFH in our kitchen. It is one of two UFH zones, both of which have their own wall mounted 5+2 programmable thermostats. The two UFH zones have a manifold with a mixer, though I have to confess I don't know where the call signal goes (both the manifold and the boiler?) I set the kitchen floor timer to come on for 3-4 hours in the morning, at a relatively low temperature (17.5°). It doesn't necessarily reach the set temperature before it turns off again, but there is usually enough residual heat to keep the temperature stable for the rest of the day. As it is the kitchen, it gets another boost of heating in the early evening (edit to add: from cooking). 

If we sit at the kitchen table later in the evening, we sometimes boost the heating and it usually responds fairly quickly (within an hour). But I have noticed that this upsets the heating routine the following day as the floor doesn't loose heat quickly enough to fire again early in the morning. 

I think a programmable room thermostat should be enough, with a bit of operator learning.