Planning to integrate a smart thermostat

The next thing I want to do with my HE is to integrate a smart thermostat with it.

We currently have a "dumb" Honeywell, their T4 Pro model, that for all it's lack of smarts does a fine job of maintaining temperature. Since both my wife and I are retired, when we're not on vacation we're at home much of the time, so running a basic program to adjust temperature throughout the day is plenty for us.

The two things we'd like to do are:

  1. Change the program when we go away on vacation to maintain a minimum of 35 F, this is to prevent the house getting too cold if it gets chilly in winter;

  2. Set up the ability to remotely come out of vacation mode and return to normal. Imagine we're returning from England after a six week trip to see my family in the fall. The thermostat has been in vacation mode the whole time, so we'd be coming home to a really cold house. The aim is to turn on the heat a few hours before we return so we arrive home to a nicely warmed up house.

I got a recommendation for Ecobee, but decided against that because while it does have good integration with HE, it's cloud based, and I really don't want to go there.

I'm really interested in the Honeywell T6 Pro Z-wave because installation will be a complete no-brainer: tear the T4 off the UWP mount, and plug the T6 onto it. Boom, job done.

Left to it's own devices, it looks as if the T6 is pretty similar to the T4. It's programmable so I can change the temp through the day just like I do now. It's just getting vacation mode working that's the trick.

HE has a driver for the Honeywell T6 Pro Z-Wave, so that means the only thing I need to figure is can I use this driver, under control of a custom app I'd have to write, to take the thermostat in and out of my vacation hold mode?

Unlikely you'd need to write a custom app. You can probably do this pretty simply from Rule Machine or even one of the more basic rule engines.

I use ecobee, works quite well, but I do understand both the local-only issue and the appeal of the drop-in replacement. There are lots of threads here about the T6 and people seem to have good luck with it.

I’m no expert on this, but here’s some anecdotal information. I was in the same place a couple weeks ago, and I ended up getting the Lux Konoz thermostat. It’s a dumb one as you said, and I just connected it directly to HE and used the built in Thermostat Scheduler app. All the programming is done in the app, and I base it all off the Hubitat modes, which would make creating a vacation mode simple enough. So far this setup hasn’t missed a beat. It’s kind of exactly what I want, stupid simple, changes when it makes sense to me, and I don’t have to do anything. For what it’s worth.

I have also had great sucess with the Ecobee for the last 5 years. The Ecobee suite software is also so robust you will be hard pressed to find a automation that isn't programmed into it's helpers already. The Vacation mode is also a automatic thing with Ecobee. You wouldn't need to program anything.

Though Ecobee is cloud based it will completely work without the cloud. It is just certain advanced functions and remote access, that may not function. I have had very few occasions that the cloud has been unavailable and have had may one time where a outage impacted something I was doing.

Yeah, Rule Machine would be enough, since it can use a call to a local endpoint as a trigger. :+1:

Ordered the Honeywell T6 Z-wave from Amazon, it's the ease of installation that made me go that way. I get to save the cost of getting someone out to remove the T4, and attach (e.g.) an Ecobee, along with the work needed for a different mounting plate.

The universal wall plate that Honeywell use is already on the wall, and has the wires attached, so it's just a case of pulling off the T4 and plugging in the T6. Plus the integration available looks rock solid for it, I don't even have to rely on a generic Z-wave thermostat driver, the T6 is supported directly.

As long as I can use Rule Machine to get it in and out of "vacation hold" mode, I'm done. And even if not, ball park estimate is it'll be less than 100 LoC for a custom app. This just isn't rocket science. :slight_smile:

FYI, that thermostat works better with the Generic Z-Wave Plus Thermostat driver.

Thanks for the heads up. I'll give that a try, it should do. It's not like I'm trying to do anything particularly tricky.

There’s a contradiction hiding in there …

The Honeywell T6 Pro arrived this afternoon, and was duly installed.

Everything looks perfect, it's got three "modes": "Home", "Sleep" and "Away". I've got them all set up like I want them. With both of us being retired, it's just "Home" during the day, and "Sleep" at night. It even successfully switches from "Home" to "Sleep" at the appropriate time.

The only thing I haven't figured how to do is to switch between these modes from the HE. What I want is either one of the following:

  1. Switch between "Follow schedule" mode and "Away" mode, such that in "Away" mode, it stays there indefinitely, until told otherwise, but when instructed it returns to schedule mode, toggling between "Home" and "Sleep" based on time of day..

  2. Maintain the three modes, but turn off the scheduling and have the HE switch as needed, most likely using Rule Machine to drive it all.

As a last fallback, I can put the whole thing in the HE, but that seems really gratuitous: setting the target temps from the HE on a mode change, since the thermostat already has that capability. Why bother reinventing the wheel?

This last question probably belongs in a separate thread, but without the source to the driver, what ways do I have to enumerate all methods that can be called on an arbitrary device? Knowing that would let me look at everything I can do to the thermostat, and possibly come up with a solution. I'm also about to faceplant into this issue with my Night Light app, but that's a completely different story.