Most of the z-wave thermostats (I have the Trane Schlage ones) state that they are not for use with radiant heating systems.
Can anyone recommend models that are compatible with radiant heating? Thanks!
Should I interpret the lack of response as indicating that there are no radiant heat solutions?
-David
In fact there is no Z-Wave high voltage thermostat.
Therefore if you are speaking about electric radiant heater, there could be a problem.
These are the 2 solutions I’m looking at:
[ul][li]One is to use a regular HVAC thermostat coupled with a specific relay (will provide the model it it is your case)[/li]
[li]The other is to use a specific Aube Thermostat (TH114 Series) and add a Z-Wave relay to switch the thermostat in “away” mode when required.
[/li][/ul]
These are just ideas. I haven’t tried anyone of these solutions yet.
What kind of radiant heat? If you are talking about in floor then you are correct, there are none. I have the Schlage thermostat and I believe that it works with water baseboard radiant heat. I hope so since the house I just bought has such heating.
In fact there is no Z-Wave high voltage thermostat. Therefore if you are speaking about electric radiant heater, there could be a problem.
Huogas,
I don’t believe that it is electric radiant heat in my situation. It is hot water from a boiler (the same boiler that heats water for my taps and for my baseboard heating) that is pumped through pipes that are inside the concrete floor. Does that change anything?
-D
@Tripledad
I think the thermostat you mentioned will do the job David.
When they say that it won’t work for radiant floor heating, I think they refer to electric radiant floor heating.
That’s said, maybe someone else could confirm or infirm ?
Hot water boiler-based baseboard and floor heating is no different than forced air where the thermostat is concerned. The Trane Zwave thermostat is quite a nice unit, and can be found a some really inexpensive prices at Radio Shack, I believe.
If your system is electric, that’s another story. I pity the person who has to pay that monthly bill, but I digress… I don’t think there is any current Zwave thermostat that will do the job by itself. I have been looking for a Zwave thermostat to handle a 120V circuit for my warehouse and have found nothing to date that is self contained.
I digress too, but it depends a lot where you live… It is cheap energy in some places… 
You’re absolutely right. Around here, natural gas is far cheaper than electricity. I forget that in other parts of the world nat gas is either non-existent or very expensive.
The relay option is the safest but will require a box to place the relay in to make it code compatible. At least until a high voltage thermostat becomes available. Then of course it will have to have a 24V power supply, and 24V coil on your relay. Be sure it is all either AC or DC not a mix as your power supply or relay coils will overheat and fail.
In my case I have a resistance heater in my guest room, it’s always cold in winter. I installed a high voltage thermostat then a z-wave on/off switch to power it as a master. I know, this will not remotely control the temperature, but it does make sure my my bill does not skyrocket when my guests leaves and forgets the heater.
The misnomer in the instructions on many thermostats that they connot be used on radiant or millivolt is true only to a point.
Yes these thermostats will not control a 120 or 240 volt load, nor will they control a milivolt load by themselves.
There are many code compliant and simple ways to acheive Zwave thermostat usesage for these uses.
I do these installs all the time.
I am building a 12 zone radiant floor heat system with Zwave.
You are right that the available thermostats are not ideal for this. they will work like any other traditional 24v thermostat will. The radiant heat thermostat typically has a more intelligent ON vs OFF time to evaluate the temperature rise in the room prior to getting to the selected temperature. By the time you have heated the floor enough to change the room temperature you have too much heat stored in the floor and the room temperature will exceed desired temperature. The same happens during cool off. You can minimize this by controlling the water temperature going in to the floor, or by writing a script to only allow you circulating pump to operate for a limited time, then look for desired temperature trend.
[quote=“knutfinn, post:12, topic:168173”]I am building a 12 zone radiant floor heat system with Zwave.
You are right that the available thermostats are not ideal for this. they will work like any other traditional 24v thermostat will. The radiant heat thermostat typically has a more intelligent ON vs OFF time to evaluate the temperature rise in the room prior to getting to the selected temperature. By the time you have heated the floor enough to change the room temperature you have too much heat stored in the floor and the room temperature will exceed desired temperature. The same happens during cool off. You can minimize this by controlling the water temperature going in to the floor, or by writing a script to only allow you circulating pump to operate for a limited time, then look for desired temperature trend.[/quote]
This was my speculation in my earlier post. Heating a slab is a dynamic process.
In my case 2 of my zones are in a basement slab controlled by Trane Tstats … setting them at 5 degrees below desired temp has worked fine. To me the big thing is even at -20 once they reach temp the heat stays very steady.