One thermostat controller to rule them all

October 19, 2021 9:40 AM

I have a weird house. It currently has a thermostat for the pellet stove, a thermostat for the heat pump (combined a/c and heat) for the bedrooms and bathroom and a thermostat for the OTHER heat pump for the dining room and kitchen. Is there any way to unify all of my thermostats with one controller/one device?
posted by arnicae to Home & Garden (6 answers total)

What would your goal be here? To me it seems normal or even desirable to have different thermostats for different zones in the home (although having each of them hooked up to a different heat source is admittedly a little unusual).

Is it that you want to be able to adjust the temp for the whole house without adjusting each thermostat separately?

If you replaced all the thermostats with networked thermostats (often obtainable cheaply from your utility company) you would be able to control all of them from your phone/computer/home assistant dealie.
posted by mskyle at 9:59 AM on October 19, 2021 [1 favorite]

It's definitely possible to do with a bunch of microcontrollers and a single device communicating with all them over wifi; if I were asked to homebrew a solution, it'd involve either 2 or 3 ESP32s (2 if you want your new control device where one of the old thermostats was; 3 if you want it somewhere else completely) with OpenTherm shields (assuming all three thermostats use more or less the same wiring setup) and a Raspberry Pi with some sort of input/output (I think there are easy touchscreen attachments) to serve as an overarching controller.

But there are almost certainly non-homebrew solutions to this as well. The APIs for most networked thermostats are open, I think, so both the major commercial home automation systems (Alexa, Google Home, etc.) and the open-source ones can talk easily to any mainstream Wifi-enabled thermostat.
posted by jackbishop at 10:04 AM on October 19, 2021

Do you want one controller that gives you independent control of each device or do you want one thermostat that controls all the devices together? The former may be possible, but the heat pumps complicate matters as they don't work as a gas furnace or electric baseboards do (they run more constantly at a variable power setting), so you can't just replace their controllers with any thermostat like you might for a furnace. The latter is probably a bad idea, because heat won't be evenly distributed. But it all depends on what exactly you want to achieve and the devices you have.
posted by ssg at 3:49 PM on October 19, 2021

There's an open source home automation software project called, well, homeautomation. It lets you control compatible hardware with your phone, a computer, Alexa/Google assistant etc. There are many many different types of hardware setups for it.

I bought 3 zwave thermostats, a zwave receiver and set it all up. I can control them all from a panel or tell Alexa to turn one up or down, or schedule changes etc. I can tell the system to turn down the ac when I leave. I can also record temps to a database and graph it all.

It's not trivial but it is doable. If this sounds like your jam I could point you to some resources and help you out
posted by RustyBrooks at 5:03 PM on October 19, 2021

I think RustyBrooks means Home Assistant.
posted by flimflam at 2:47 AM on October 20, 2021

Whoops you're right, it's home assistant.
posted by RustyBrooks at 7:27 AM on October 20, 2021