Hello, I'm very excited to be getting a hydronic radiant floor heating system put into my multi-level home renovation. The HVAC design is calling for 15 zones across 3 floors plus the basement. There will be slab sensors used for each zone as well. Can anyone recommend a Wi-Fi Thermostat to help control all these zones? I presume I will need 15 of these? It would be ideal to control the zones wirelessly especially if leaving town for a few days. Thanks for any advice!

How many square foot total. A zone is typically an area you want to keep at a specific temperature. 15 sounds like a lot to me, Do YOU think you have 15 separate areas to control separately?

Oops, Double tap...

Why so many zones? Two to four zones are usually way more than adequate for most large residences. How are you thermally isolating the slabs and walls for all of these zones?

Why do you want wifi thermostats? Hardwired thermostats are plentiful and are not subject to hacking. There are plenty of home automation/security systems that allow you to control your HVAC system (including thermostats) remotely over the Internet using a PC or smart phone, etc.

Who designed this system and made these recommendations? Do they actually have any experience designing hydronic heating systems? You might benefit from getting a copy of John Sigenthaler's "Modern Hydronic Heating".

I like the idea of having maybe one wi-fi thermostat as it can used as piece of mind for house checking when away, though you can do the same with DIY security systems. However, it almost sounds like the designer is missing the point with radiant heat, or perhaps maybe my research is off. With radiant, programmable thermostats are not used/needed as much as the idea is the occupants are not going to have have several cycles/periods in the day where the room temperature decreases than increases.

It might be that the hydronic loops are being confused with zones?

Very good thought Ronmar! 15 loops at 12" spacing could provide coverage for 4,500 sf.

You won't be dialing back the temperature at night with high mass slab hydronic heating. You will just maintain a steady comfortable indoor temperature.

Thanks for your comments and expertise, everyone. The HVAC engineer (seemingly experienced) drew those "zones" all with individual thermostat controls, and the hydronic heat installer who does many installs yearly agreed to do it. I see it as an advantage so you can fine tune each individuals room/bathroom to just the right comfort level. The house is fully spray-foam insulated with good thermal windows. I thought there might be an obvious go-to thermostat or Wi-Fi thermostat to help deal with all these zones, especially in perhaps turning them on/off all together when leaving for a few days or when coming back. I agree that programming it for cycling overnight may not be possible with the thermal mass of Agilia Screed A which we will use for the overpour of the loops.

If I were doing a mass floor, I would not do 15 separate thermostats. I would probably only do one per floor. If I wanted an area warmer or cooler than an average temp, I would adjust the flow to those loops so it runs a little warmer or cooler than the floor zone set temp... But that is just me, you are welcome to make this as complex and expensive as you like

I'd say multiple zones per floor is fine, even quite desirable. For example you likely would prefer your master bath floor to be warmer than your other floors. We have one zone each in the basement and 2nd floor and 4 zones on the 1st floor. It may depend how you are zoning, pumps vs valves. You could have a ton of zones using zone valves (every loop could be a zone). We kept it simple (I think, lol) and used zone pumps and just have a pump sized for each manifold.