I’m going to replace my whole-house HVAC system and I’m wondering what brands have better track records for being more “hacker” friendly. Namely what brands lock you into their own smart thermostats and void the warranty if you replace them. Or which brand’s smart thermostats are nice to integrate with or work well with HA?
i have never heard of a hvac that does not work with standard house thermostat wiring or require any type of specific thermostat for warranty purposes… is that a thing?
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From this article: A Few Things to Know about Wi-Fi Thermostats | Comfort Flow Heating
Compatibility is what’s at issue. An advanced thermostat with smart technology may not be able to work well with the current HVAC system. It could even cause damage to it. This is why putting in a new thermostat may void the warranty.
I suppose I just have to ask the people giving me bids what the deal is. Just wondering if anyone here has had experience with this and can point me in the right direction.
Go for any midea branded hvac, and use an esp8266 module?
Normally midea bases hvac’s use an osk103 wifi module, but these have been reverse engineered and now also work with esphome 
This is the list so far, and still growing 
I, and many others, confirm this works and is even way cheaper the the original wifi dongle 
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Thanks but sadly all the US models are mini-splits or window units. I’m looking for whole-home systems.
Wouldn’t know about whole house, but if you are referring to multi-split, also that is confirmed working 
Basically any hvac model working with osk103 or osk102) wifi module will work (theoretically)
I selected the Lennox brand and went with the iComfort e30 thermostat.
I connected the system to HA through the HomeKit controller.
Very pleased with my decision!
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Unless I am missing something, that link just states that a “smart” thermostat may cause damage, but does not provide any information as to how it could cause damage.
If the HVAC system uses the standard set of wires (RWGY) for control, then any thermostat should be fine. Whether that be a commercial WiFi thermostat, or you with a thermometer twisting the wires together when the room is cold.
The only requirement here is that the thermostat not do something stupid like call for heat and cooling at the same time. Most modern HVAC units will lock this out, but some will not. However that seems to be a requirement of all thermostats, not just “smart” thermostats.
Did you read the list @aceindy posted?
As you can see, I explicitly setup a market for the units. There are a few sold in the US market, namely Mr.Cool, Pioneer or Toshiba. 
Unfortunately, these are not really what’s considered a whole house HVAC system in the US. I was an HVAC installer and haven’t heard of them providing a US typical furnace and separate A/C or Heat Pump with whole house ductwork.
Personally, I have a Bryant system with an ecobee thermostat directly provided from the company that I got the system from. Ecobee makes a range of thermostats they call “Pro” that are the same as the 5 series, but come with a longer warranty if installed by Bryant techs. Ecobee has the same agreement with Carrier, which is nearly the same as Bryant.
This is exactly why some warranties can have some requirements of not using “custom” components. There still are some A/C units too dumb not to cycle the compressor on and off repeatedly. Some low budget setups still rely on the thermostat to have a timed lockout. It’s sad.
I just received a good quote an a Carrier, one “silver” level with an Ecobee 3 Lite Pro and one “gold” with an Infinity controller. I see there appears to be HA integration for both of them.
Using HA, will I be able to control the system completely? What I would like to do is monitor the bedrooms at night, if any of them gets too hot or cold compared to the rest of the house, kick on the fan. If one of them is too hot and the overall house temperature is average, run the heat or AC. I’m willing to write my own code to accomplish this.
Sorry for all questions, I’ve done a fair amount of googling but it’s hard to tell what would be possible with all the combinations of components. Thanks to everyone for the information so far!
I can confirm this is possible with the ecobee and additional sensors. I have the Pro version 5, which is nearly identical to a version 4 and has Alexa built-in. This may use different sensors than the 3 lite.
I setup a toggle switch to kick the fan on for 25 minutes of every hour when I notice my basement temperature is much cooler than the first floor or my bedroom. This works great! I haven’t automated yet, but I know it’s entirely possible. One thing I discovered, when the ecobee thermostat switches schedules, my toggle is reset and when it returns to that schedule (night, work, etc.) it remembers what the toggle was at.
Edit: I recommend looking at the ecobee integration docs in HA to see all the additional pieces you can control.
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Is this a function of ecobee or HA? Specifically does HA allow you to integrate any old temperature sensors into the system and use that data to control the ecobee? I’m leaning towards the Infinity system as it has a higher efficiency but I cannot tell what commands are possible. Do most of these smart thermostats at least allow “fan off/on”, “ac off/on”, and “heat off/on”? Or is it just “temp up/down”? It must allow me to run the fan when I want…
Ecobee has the functionality built in with their own sensors and that’s what I use. I imagine you could give control to HA to use other sensors as well, but I like the ecobee occupancy sensors myself.
The ecobee fan control isn’t a traditional on/Auto configuration. They use a # of minutes per hour setup. 60 minutes per hour would be “on”. You can set this up in HA as well andwith automations you could trigger with any temperature sensors if you choose.
I’ve stuck with the ecobee schedules myself, because they just work well with their occupancy and temperature sensors. I manipulate the fan run time with HA.
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