Thermostat - Aux Heat Control

Welcome to the Wyze User Community Forum @king.robert.j! :raising_hand_man:

As I stated in my post, I was trying myself to get an understanding of the logic and temp deltas used to control the Aux\Emerg heat from posts I read.

I posted links within my posts to the resources I was reading. Follow those links.

What I have learned though, is that the Wyze Thermostat is not very efficient at managing use of Aux\Emerg heat.

@SlabSlayer Thank you and glad to be here. I have some Wyse cameras and a vacuum cleaner

The only external link I saw in the thread here was a picture of the emergency heat. That said, this thread was the most promising in that the 5f differential you mentioned aligns better with what I want, economy over comfort. I was just hoping to find official Wyze documentation, or did you mean by links what others had found out?

FYI I did search the forum and reach out to Wyze before posting. Nothing on the forum and so far Wyze is just giving me irrelevant cut and past responses. I’ve got a dual zone system, so trying not to have to spend $400+ which Nest and Ecobee will have me doing.

BTW, nobody really does all that good a job on heat pumps/geothermal. But it’s the abuse of AUX heat and/or not understanding it that causes the most problems.

Thanks for your comments.

If you do find it, please share. The only documentation that I have ever found for the Thermostat can be found in the Wyze Knowledge Articles:

And what should be loosely referred to as a User Guide:

I looked around for official documentation on the 5° 30m emerg\aux heat programmed logic but haven’t found any. I believe I picked that up from reading the OP’s post.

There are many mysteries of logic and behavior hiding behind that little black screen that have yet to be uncovered and documented.

I’ve experimented with forcing the Second Stage Heat to kick in… I haven’t had any luck with 5° but if I bump the thermostat up 10° over the current inside temperature, the Second Stage Heat comes on.

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Next best thing, a quote from Wyze tech support:

The 4F temp differential is in the Honeywell range for “economical” use of a heat pump so I’m good with that, and also the timeout is normal for the algorithm’s, although I’d have wished Jennifer had disclosed the timeout. Even better if both these numbers could be programmed by the users. The issue with 4F is if you make big jumps with your program settings.

As I mentioned elsewhere, using outdoor temperature for GeoThermal AUX heat decision is a big no no since it uses the earth as a heatsink, not outdoor air. I imagine there are workarounds but contemplating returning the units I bought (not installed yet).


Thanks for the information!
She said, " outdoor weather is used to determine when to run only the Aux heat"…
As far as I can tell, it doesn’t know what the outdoor heat is.

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I’ve seen some talk here it uses internet weather to determine outdoor temperature. She of course doesn’t state that, but I asked for a clarification in a follow up.

This feature for a standard heat pump is a good thing and I’ve seen complaints in posts from 2020 it wasn’t sensing outdoor temp. This ‘feature’ for geothermal is the opposite, a bad thing.

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Thanks for posting that!

Not only is the internet sourced outdoor temp “data” an issue since there is no capability for an external temperature sensor and far too little room in a 4° delta for local temp variances, but the “behavior settings” mentioned that determine the “default run time” are also a complete mystery. Wyze has never revealed the secret behind any of these settings. What are they?

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So I’m revisiting the “Behavior” settings… because I just set it for max Savings.
The descriptions for the settings are not helpful, so it was just a guess.

This could be the solution to my problem if they would provide some good information here.
They could start by showing me what the system thinks the Outdoor Temperature is…

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Bit by bit I getting more data as support responds to me. 35F seems to be the point it ONLY runs AUX heat, which for a Geothermal user, would cause a massive unnecessary electric bill since we reference ground temp, and not air temp

As such, I informed support they should stop marketing the product as GeoThermal compatible, as it clearly isn’t. The good news, and I say this as a IoT firmware developer, is this would be a easy fix for them, just define two types of heat pumps and have Geothermal not respond to the <35F flag. Now if they can or will do this, remains to be seen but I hope so as I won’t need to return my units I just ordered.

Below latest dialog from support. Bolding is mine

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Thanks for staying on this and sharing!
The statement that the system will only use Aux Heat below 35° is absolutely Not True!
That’s my whole problem…
It’s trying to run the Heat Pump when it’s freezing outside!

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As it would be with a air to air heat pump. In my case, geothermal I NEVER want the AUX heat on unless there is a system failure.

Sounds like the left hand doesn’t know what the right hand is doing at Wyze, OR the change logs for the firmware are lagging. In the other thread here in the forum I started, there is I think a wyze employee. Worth taking a look at


Jennifer mentioned that the information came from a “Team” they are working with… My guess is that this is something that Wyze has outsourced. They purchased what they have, they probably don’t have anyone in-house that can make updates… Programming thermostats is not something they are going to need every day.
Anyway, looks like they’ve given themselves a way to address the issues through the “Behavior” settings. I can’t tell if it does anything at the present time. Perhaps it’s just a Place Holder for future development. :relaxed:
Seems like Behavior would just control First Stage and Second Stage Heat as well as the Fan.
They could start by displaying the outdoor temperature. In fact, this would be a nice feature! This would confirm to the user that the system knows the current environment.
Second, they need to let geothermal users adjust for their conditions.
It would be good to have a “Story Board” of what the Behavior screen sould look like for the user.

This is a serious issue!
My electricity usage went up 432 kWh from this time last year! That’s a 61% increase!

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Wouldn’t it be nice if they could show the current, local temp?
The “Smart Life” App does this. (For Smart Life devices)
My previous thermostat did this…


As a wrap-up here, here is my last exchange with Wyze. Disappointing and I concur @oneilldm in that they seemed to have outsourced the firmware development. I had hope to keep my home entirely ‘Wyze’ but it seems that isn’t possible. Not turning my back on their new products but it won’t be a thermostat. The good news is the return process seemed to be seamless and my refund already posted.

Thank you. I’ve returned all your units and purchased EcoBee, which works properly with GeoThermal systems. But just to be clear, you should stop claiming the thermostat is GeoThermal compatible. To make that claim, at a minimum you’d need to ignore outdoor temperature. It’s a simple fix and it’s a shame you are unwilling to consider it.



On Fri, Feb 3, 2023 at 12:25 PM Support <> wrote:

##- Please type your reply above this line -##

Your ticket (27xxxx) has been updated. To add additional comments, please reply to this email.

Feb 3, 2023, 9:25 AM PST

Hello Jeff,

Thanks for the update and I truly apologize for the delay in getting back to you. I’ll be sure to look into this further.

I have made a follow-up with the team about your question and I’ve confirmed that there is no way to disable the outdoor temperature sensor.

The Wyze Thermostat is designed for the most typical systems and should be compatible in most cases unless it is a system that simply isn’t compatible. Our compatibility checker can tell if it is compatible based on your thermostat wirings or the terminal labels you will select on the wire selection page.

While we understand that there are some systems that can pass the compatibility checker but work differently than what your system usually does, we can say that that system is not compatible, especially if using the Wyze Thermostat to that system will cause issues in the long run.

I understand that it will be inconvenient if the Wyze Thermostat’s outside temperature sensor cannot be disabled. As much as we want to, we don’t have a way to have that feature disabled. Also, the Wyze Thermostat can only support one of the four accessories: emergency heat, humidifier, dehumidifier, and ventilator, which can be connected to the * terminal. It doesn’t support ground temperature sensors.

I would like to sincerely apologize if you felt disappointed and I trust that I have answered your questions. Regardless, as one of the leaders here at Wyze, I would like to say thank you for working with us on our troubleshooting and for your patience in getting the answers that you need.

Please feel free to let us know if there is anything else I can assist you with. Have a great weekend!

All the best,

Jennifer Wyze Wizard


Jeff - Thanks for all your work on this and sharing the information… It’s very helpful.

Not everybody comments here but a lot of people read things on this forum.

I have one of those common systems, but mine is very inefficient when the temps are below 40°. We are having a cold streak again here in middle Tennessee and my heat pump keeps trying to do something even though the temps are below freezing. (18° right now) I understand the heat pump will try to make use of residual heat left over from my Second Stage, Gas Heat… but it’s running way too much.

Wyze is SO CLOSE to having a great thermostat…
It’s a software fix!
I’ve tried all the settings I can think of, but I’m often kicking up the setting 10° to force the Second Stage Heat to come on… Then, of course, I have to turn it back down again.
I need to be able to set it and forget it…

Anyway, once again, thanks for your help on this issue.

Glad to see the people at Wyze took care of you…

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