Hydronic floor heating Thermostat

zetoniox

Hello all,

Newbie here, with a question that I've been having a hard time with.

Installing hydronic floor heating with 5 zones. Wanting a smart thermostat that is Alexa enabled. Was thinking of using Nest's true radiant but the only thing i find on the web is bad reviews from 5-7 years ago. Haven't really found anything recent. Is Nest's true radiant still bad? or have they upgraded it and works fine now?

Also saw the Tekmar 561 which is WiFi enabled and has an app, but not Alexa enabled. If I use the Tekmar, would i need to use the floor sensor? Will I still be able to use the Tekmar app to control the system even if i'm not home?

What would you guys recommend? Is there any other thermostat that I missed or should look into?

Thanks so much in advance!!

Jose

Jamie Hall

This is in-floor radiant heating? If so, you don't want to be playing with the temperature and therefore you don't want to be using any kind of setback. At all. You want to set it and forget it. Why? Because radiant floors take a long time to heat up -- hours to days -- and to cool down -- ditto.

Other than the fact that a Nest will try very hard to mess with your temperatures (that can be disabled, but then why have a Nest?) and can present wiring problems, they work OK. For forced air heat, they're actually not too bad. For any other type of heat... they're a poor choice. I'd never use one for anything other than forced air. At least in my opinion.

STEVEusaPA

4 zones out of 6 in my home are radiant. After initial set up, I've never changed their settings in the last 10 years. Actually haven't changed the other 2 zones either.
Unless this is for a vacation home or something with long unoccupied times, a wifi stat a horrible idea in this application.

Floor sensors have their own potential problems, depending on the application and if properly installed. If you are only relying on the floor sensor you will get under/overshoot on your temperatures.

JUGHNE

I agree with Jamie and have almost the same heating set up as Steve.
I tried set back in the master bath and learned that was stupid.
All zones now have simple Honeywell Focuspro TH5000 set at 3 cycles per hour. Set and forget.

One zone is a passive solar sun room which is mostly glass, some how 74 is the right setting as on a good sunny day the system seldom runs. Also 74 for the master bath. The basement is 70.

74 may sound extravagant...….but we put this in for comfort, yes it costs money to run but because of the insulation package our bills are less than other houses this size.

In my younger days I had visions of remote control/automation. But eventually learned that these devices rule your life just like cell phones do.

BTW, 80% or so of the setback T-stats I see end up on permanent "hold" for any type of system.

hot_rod

Is its a radiant concrete slab, or a light on-top dry system? I agree the slabs are not ideal for daily setback, low mass systems can setback a few degrees and ramp up fairly quickly.

A thermostat with both air and floor sensing can be dialed in nicely with some owner attention. I've used them in bathroom radiant with a not-to-exceed slab temperature dialed in.

zetoniox

Thanks guys for your replies.... Really appreciate all your input..

hot_rod said:

Is its a radiant concrete slab, or a light on-top dry system? I agree the slabs are not ideal for daily setback, low mass systems can setback a few degrees and ramp up fairly quickly.

A thermostat with both air and floor sensing can be dialed in nicely with some owner attention. I've used them in bathroom radiant with a not-to-exceed slab temperature dialed in.

yes, it's 1.5" dry packed concrete. Doing this in 2 phases so first half of house is with sleepers installed. Will do phase 2 now but just found schluter bekotec -f so i will use that for rest of house instead of stapling down pex and using sleepers.

Jamie Hall said:

This is in-floor radiant heating? If so, you don't want to be playing with the temperature and therefore you don't want to be using any kind of setback. At all. You want to set it and forget it. Why? Because radiant floors take a long time to heat up -- hours to days -- and to cool down -- ditto.

Other than the fact that a Nest will try very hard to mess with your temperatures (that can be disabled, but then why have a Nest?) and can present wiring problems, they work OK. For forced air heat, they're actually not too bad. For any other type of heat... they're a poor choice. I'd never use one for anything other than forced air. At least in my opinion.

Thanks for your reply. I like the set and forget it aspect of it. I'm sorry but i'm not sure what setback is or does....i guess it'll be my google project tonight to learn that.

I'm starting to see that tekmar might be my best route. Who needs Alexa anyways...hahaha

Has anybody used the tekmar app before??

Dave H_2

I have a nest in my home and the radiant sense does work pretty well for my radiant floor. What the radiant sense does is learn how long it takes a room to get to setpoint and adjust the start time in order to get it there. I use setback, but just not too deep.

Jean-David Beyer

I have a fancy thermostat that allows 4 different temperatures for each of the 7 days of the week, so in theory I could set it to run 28 different temperatures a week. It is supposed to learn how long it takes to reach a desired temperature, and perhaps it did.

But the zone controlled by that thermostat is radiant slab at grade, and it takes about two days to stabilize at the new temperature after making a change in temperature, so now I set it to 69F all year long with no setback at all.

Back when I was playing around, it would normally not drop the temperature to a lower temperature until sometime the next day if I started the setback at 4 PM. Similarly for raising it again. In fact for that it took even longer because I use outdoor reset and so the actual heating supply temperatures are too low to recover in several days.

When tropical storm Sandy dropped my power for 6 1/2 days, my house temperature dropped about 10F and after the power came back on, I changed the reset curve to allow much hotter supply temperature for a coupla days until the house got somewhere near the temperature I wanted. Then I put the reset curve back where it was needed. The cheapest thermostat you can get is probably what you need if you have a system like mine.

modconwannabe

A setback is just the word for when you drop the temperature setting on your thermostat, often during sleeping hours or during the day when you're not home. For forced air that's a good idea as it save energy; for hydronic but especially underfloor radiant heating, it's better to set it to the temp you like and leave it alone. I learned that the hard way when we went on vacation and let the temps drop to the 50s on our radiant system and when we returned it took a couple days for the floor to get back to normal 72. Think of radiant as a cargo ships: hard to turn to quickly!

zetoniox

modconwannabe said:

A setback is just the word for when you drop the temperature setting on your thermostat, often during sleeping hours or during the day when you're not home. For forced air that's a good idea as it save energy; for hydronic but especially underfloor radiant heating, it's better to set it to the temp you like and leave it alone. I learned that the hard way when we went on vacation and let the temps drop to the 50s on our radiant system and when we returned it took a couple days for the floor to get back to normal 72. Think of radiant as a cargo ships: hard to turn to quickly!

Makes sense!! So basically the only need for app or wifi enabled thermostat is if one is on a long vacation and set temp back a few degrees and a few days before coming home to set temp back to normal. Or even just to check on the system making sure nothing is wrong in house. Even then it might not even be worth it.

JUGHNE

Honeywell Vision pro 8000 series has a vacation setback mode.
(maybe that is "old school" Tstat by now, seemed not possible when I put them in BTW)
Say if gone for 10 days have it come on in 8 days.

There are monitoring devices for temp and wet floor you can call for reports.....again old school....probably need a landline.

hot_rod

zetoniox said:

modconwannabe said:

A setback is just the word for when you drop the temperature setting on your thermostat, often during sleeping hours or during the day when you're not home. For forced air that's a good idea as it save energy; for hydronic but especially underfloor radiant heating, it's better to set it to the temp you like and leave it alone. I learned that the hard way when we went on vacation and let the temps drop to the 50s on our radiant system and when we returned it took a couple days for the floor to get back to normal 72. Think of radiant as a cargo ships: hard to turn to quickly!

Makes sense!! So basically the only need for app or wifi enabled thermostat is if one is on a long vacation and set temp back a few degrees and a few days before coming home to set temp back to normal. Or even just to check on the system making sure nothing is wrong in house. Even then it might not even be worth it.

WiFi stats allow you to monitor the systems from afar. I think they have a lot of value in second, or third homes. Both the owner and a local service provider can get a txt, or call if the system fails. Property managers or heating contractors can watch all or their customer's homes from one screen, with the Ecobee and others.