Bathroom radiant floor heating control

[Neurorad]

Anyone have any info on controlling a dedicated radiant floor heating thermostat?

Haven't chosen a home controller yet, I've only been looking for a year.

But I'm trying to think ahead on this bathroom renovation.

I know the HAI Omnistat2 lists 'radiant heat' in the product description, but it looks so different from the dedicated (non-controllable) radiant floor thermostats.

Any info would be greatly appreciated. I've already spent hours looking online.

 

[beerguy]

Anyone have any info on controlling a dedicated radiant floor heating thermostat?

Haven't chosen a home controller yet, I've only been looking for a year.

But I'm trying to think ahead on this bathroom renovation.

I know the HAI Omnistat2 lists 'radiant heat' in the product description, but it looks so different from the dedicated (non-controllable) radiant floor thermostats.

Any info would be greatly appreciated. I've already spent hours looking online.

Is it electric or hot water radiant heat. I have hot water (actually glycol I think) radiant heat and the thermostats control solenoid valves based on demand for heat. These solenoid valves are 24 volt so they were always controlled by a standard thermostat. I replaced the existing thermostats with HAI RC-80's (I think that's the number) single stage heat thermostats. It all works fantastic. I have this in a vacation home and primary residence. One place has an ELK and one an HAI and both control the t-stats perfectly.

If it is electric you'll need to know what voltage the stat needs. Some are line voltage which will make things more complicated as you'll need a contactor/relay between the stat and the heater.

Hope that helps.

Pat

 

[tmbrown97]

Assuming you're talking in-floor radiant head (under tile, etc):
most radiant heat systems have a specific controller they're meant to work with - they monitor temperature, etc. They have fancy digital ones, or simple dial-based ones. Seems to me, for HA based applications, the more manual switches that you can just switch power on would be best. I'll be finding out in about a month when we retile the Master bath.

 

[SteveQ]

I agree with Todd. I have 2 bathrooms with electric floor heat (under the tiles). They have special thermostats that are part of the system. One is programmable the other is not. I have the non programmable system connected to an x10 fixture module. Homeseer turns it on at 6:30 AM and Off at 10:30AM only when the outside temperature is below 45 degrees. This has been working great for 2 years.

Steve Q

 

[86turbodsl]

You probably don't want to do setback on radiant heat zones. the lag time is excessive, and you won't be able to get it back up to temp
on short notice. Too much thermal mass. I have radiant baths in my house, and my contractor recommended against setback thermostats. spend your money on better insulation instead. better payback.

 

[Neurorad]

Is it electric or hot water radiant heat. I have hot water (actually glycol I think) radiant heat and the thermostats control solenoid valves based on demand for heat. These solenoid valves are 24 volt so they were always controlled by a standard thermostat. I replaced the existing thermostats with HAI RC-80's (I think that's the number) single stage heat thermostats. It all works fantastic. I have this in a vacation home and primary residence. One place has an ELK and one an HAI and both control the t-stats perfectly.

If it is electric you'll need to know what voltage the stat needs. Some are line voltage which will make things more complicated as you'll need a contactor/relay between the stat and the heater.

Hope that helps.

Pat

Thanks so much, Pat. Stupid me, yes, it's electric.

Contact/relay. Stored on neuron #1.

Assuming you're talking in-floor radiant head (under tile, etc): most radiant heat systems have a specific controller they're meant to work with - they monitor temperature, etc. They have fancy digital ones, or simple dial-based ones. Seems to me, for HA based applications, the more manual switches that you can just switch power on would be best. I'll be finding out in about a month when we retile the Master bath.

Manual, simple thermostat. Neuron #2.

GL with the remodel.

I agree with Todd. I have 2 bathrooms with electric floor heat (under the tiles). They have special thermostats that are part of the system. One is programmable the other is not. I have the non programmable system connected to an x10 fixture module. Homeseer turns it on at 6:30 AM and Off at 10:30AM only when the outside temperature is below 45 degrees. This has been working great for 2 years.

Steve Q

Thanks. Special thermostat, part of the system - not 3rd party. #3.
Non-programmable. #4.

You probably don't want to do setback on radiant heat zones. the lag time is excessive, and you won't be able to get it back up to temp
on short notice. Too much thermal mass. I have radiant baths in my house, and my contractor recommended against setback thermostats. spend your money on better insulation instead. better payback.

No 'setback thermostat' (had to google that one) - neuron #5. Not programmable.


Wow!

I think that answers 90% of my questions. You guys are awesome!

Use the thermostat that ships with the kit, choose the non-programmable/non-setback t-stat option.

The 10% question - how to control it?

In the last 15 hours, I've been leaning toward HAI although their materials don't look like the highest quality, on a webpage.

Any wireless suggestions for control, short of X10?

 

[dougmeredith]

You probably don't want to do setback on radiant heat zones. the lag time is excessive, and you won't be able to get it back up to temp
on short notice. Too much thermal mass. I have radiant baths in my house, and my contractor recommended against setback thermostats. spend your money on better insulation instead. better payback.

Smarter thermostats learn the lag and turn on the heat early so that you have the temperature you want ant the time you specify. Great for typical mornings. Lousy if you come home from work mid afternoon due to a snow storm and want warm floors.

Doug

 

[86turbodsl]

You probably don't want to do setback on radiant heat zones. the lag time is excessive, and you won't be able to get it back up to temp
on short notice. Too much thermal mass. I have radiant baths in my house, and my contractor recommended against setback thermostats. spend your money on better insulation instead. better payback.

Smarter thermostats learn the lag and turn on the heat early so that you have the temperature you want ant the time you specify. Great for typical mornings. Lousy if you come home from work mid afternoon due to a snow storm and want warm floors. :angry:

Doug

Depends on how your house is built. Say you have a house out west or down south built on a slab. You put radiant heat in the rooms. You put a setback thermostat on it and tell it to
stay at 60 during the day and 70 at night when you're there. The 4" thick concrete in that house takes 24 hours to change 10 degrees. (that's pretty typical) I would call that a high mass system.
Alternately, you have an electric grid laid on top of the subfloor and embedded in the thinset that the tile is bedded in. I would call that a low mass system and it would take an hour or two to get
up to temp.

Unless you know which setup is appropriate for which room, you can't just say "get a smarter thermostat" It doesn't necessarily work.

 

[dougmeredith]

Unless you know which setup is appropriate for which room, you can't just say "get a smarter thermostat"

Then I'm glad I didn't.

Doug

 

[personalt]

This also depends on what your goal is.. Are you looking to use this to really heat the warm or just want the warm floor effect?

I have a 6 zone underfloor radiant heat system. Uses tekmar controls(not hooked up to home automation yet as their gateway is new, $1000+ and requires a mac).

On avererge days my modulating boiler by design pushes water that isnt that much hotter then the room so you dont get the warm floor effect. but you get a room that says very well on the temp that you require and unlike forced it doesnt feel cold 30 seconds after the heat turns off.

some peoplle just do the electric pads in the bath to give warm floor feel.. if so I would consider a timer that you could control with an automation system.

 

[86turbodsl]

This also depends on what your goal is.. Are you looking to use this to really heat the warm or just want the warm floor effect?

I have a 6 zone underfloor radiant heat system. Uses tekmar controls(not hooked up to home automation yet as their gateway is new, $1000+ and requires a mac).

On avererge days my modulating boiler by design pushes water that isnt that much hotter then the room so you dont get the warm floor effect. but you get a room that says very well on the temp that you require and unlike forced it doesnt feel cold 30 seconds after the heat turns off.

some peoplle just do the electric pads in the bath to give warm floor feel.. if so I would consider a timer that you could control with an automation system.

Agreed. Another data point. My house (under construction still) has hydronic radiant heat in the main floor under hardwood and tile and radiant in both upstairs baths under tile. I also have radiant in both concrete slabs in basement and garage. The system is primarily water to water heat pump (geothermal) with a standard boiler as backup for extreme cold. We also put in ductwork for AC in the summer that's zoned to turn off the downstairs when heating. The preheat tanks are also setup to take future solar panels. We've got about 10 thermostats and about 13 zone valves. My HVAC guy is a buddy I went to engineering school with. We couldn't find anything for a controller that wasn't custom, so eventually we put in a PLC from Automation direct. DL-06 with RTD temperature module for monitoring the tank temps. I think I paid about $135 for the controller, and $100 for the RTD module. The downside is that I have to program the controller, but I also have the capability of putting in a module on the PLC that is ethernet for automation for about $200. The PLC is COMPLETELY overkill, but it will do the job. Thank GOD I have some experience with this stuff or I'd be out like 5K to get a custom controller built.

Radiant is beautiful because you feel comfortable more of the time than a forced air hot/cold cycle.

 

[personalt]

I have 6 zones with a setup from tekmar controls. I think they could do as many as you have but not sure the cost. I have a boiler controler plus a 6 zone controller(the biggest I think they make). I think you can piggyback another one on but honestly I am not really sure.

the only downside I see to the tekmar controls is that the dont really have a good gateway. They have one that is supposed to work via a MAC computer but no RS232 or TCP/IP interfaces. I am not joking about the MAC....

I did three 'major upgrades' in my house. a composite slate roof, a 3 jet shower faucet and this 6 zone radiant floor. I think the floor is my favorite..

For any DIY guys out there... NRTRadiant is who designed mine. The nicest guys you can ever work with. The design plans they come up with are really well done and calculated out to the fullest.

This also depends on what your goal is.. Are you looking to use this to really heat the warm or just want the warm floor effect?

I have a 6 zone underfloor radiant heat system. Uses tekmar controls(not hooked up to home automation yet as their gateway is new, $1000+ and requires a mac).

On avererge days my modulating boiler by design pushes water that isnt that much hotter then the room so you dont get the warm floor effect. but you get a room that says very well on the temp that you require and unlike forced it doesnt feel cold 30 seconds after the heat turns off.

some peoplle just do the electric pads in the bath to give warm floor feel.. if so I would consider a timer that you could control with an automation system.

Agreed. Another data point. My house (under construction still) has hydronic radiant heat in the main floor under hardwood and tile and radiant in both upstairs baths under tile. I also have radiant in both concrete slabs in basement and garage. The system is primarily water to water heat pump (geothermal) with a standard boiler as backup for extreme cold. We also put in ductwork for AC in the summer that's zoned to turn off the downstairs when heating. The preheat tanks are also setup to take future solar panels. We've got about 10 thermostats and about 13 zone valves. My HVAC guy is a buddy I went to engineering school with. We couldn't find anything for a controller that wasn't custom, so eventually we put in a PLC from Automation direct. DL-06 with RTD temperature module for monitoring the tank temps. I think I paid about $135 for the controller, and $100 for the RTD module. The downside is that I have to program the controller, but I also have the capability of putting in a module on the PLC that is ethernet for automation for about $200. The PLC is COMPLETELY overkill, but it will do the job. Thank GOD I have some experience with this stuff or I'd be out like 5K to get a custom controller built.

Radiant is beautiful because you feel comfortable more of the time than a forced air hot/cold cycle.

 

[AnotherOne]

I have 6 zones with a setup from tekmar controls. I think they could do as many as you have but not sure the cost. I have a boiler controler plus a 6 zone controller(the biggest I think they make). I think you can piggyback another one on but honestly I am not really sure.

I'm assuming you have the digital controller. I have a 10 year old system with an analog tekmar controllers with 2 boilers and 15 zones and two 75 gallon hot water tanks indirectly heated via the boilers. I've had very few problems with the system other than the zone control valves breaking (I'm using honeywell vc controllers, and bought a few extras off ebay).

I'm using my elk m1 to control 2 of the zones, but in a rather indirect way. The elk controls a relay that emulates a temperature probe via resistors. So the thermastat(s) are all in the boiler room with the tekmar and I'm using the keypad temperature sensors, time of day, and outside temperature to trigger the relays. If the relay is off, the thermastat thinks it's 75 in the room and if it is on, 65. Then in the heating season, I just set the termastat to 70.

Why would I go to all this trouble? We'll the zones are the entry ways to the house and the opening and closing of the doors during the winter was causing the rooms to either be too warm or too cold. So with a few (like 10 per zone) rules I can keep the temperature rather constant. And if it's too cool, I just press f2 on the keypad and it turns on the zone for an hour (or more depending on a few rules ).

So, my question is there any reason to upgrade to digital contols?

 

[tmbrown97]

hey - if you've got something that works, why screw with it! You'll usually find that the addition of a $200 control tends to result in another $600 in upgrades elsewhere to support it...

If anything, I'd possibly add some well-placed elk temp sensors to automate the rules a little better.

Curious though - the OP - was he talking about the under-tile radiant heat strips, or this in-floor hot-water-piped type radiant heat? I'm just curious, because there were recommendations for each above - curious if he got the right info. But, he's only got two posts, on this page - so maybe he got what he was after...

 

[Neurorad]

hey - if you've got something that works, why screw with it! You'll usually find that the addition of a $200 control tends to result in another $600 in upgrades elsewhere to support it...

If anything, I'd possibly add some well-placed elk temp sensors to automate the rules a little better.

Curious though - the OP - was he talking about the under-tile radiant heat strips, or this in-floor hot-water-piped type radiant heat? I'm just curious, because there were recommendations for each above - curious if he got the right info. But, he's only got two posts, on this page - so maybe he got what he was after...

You bet I did! Thanks so much to everyone.

The best T-stat for my needs would be a simple 'on/off', that is not programmable.

Electric radiant floor heat.

My free time (what am I saying, I'm at work) has been consumed by online HA learning!