Thermostat - Aux Heat Control

I have a Dual Fuel Package Unit (Heat Pump/Gas Aux Heat).

I’m not sure I understand what makes the Aux Heat turn on.

I believe I read somewhere that the Heat Pump will run for 30 minutes and if it can’t increase the heat in your home, it will turn on the Aux Heat.
That’s too long!

I also believe I read somewhere that if there is more than a 5 degree difference that the Aux Heat will turn on.

I just installed this last September…
I’m concerned that my Heat Pump is going to be running too much.

So my question is… Is there a good way for me to control the Aux Heat?

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I’m still hoping to get some information on this topic…

We are back in freezing weather again and it’s running the Heat Pump!
Eventually the Aux Heat comes on but it takes too long!
Surely this is an even worse problem for people further north!

What makes the Aux Heat come on?


I’m in a similar boat except I can’t tell if my aux comes in at all. I woke up with it 10degrees below my set point. Ended up manually turning aux on to warm my house up.

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From what I have been reading, there are two ways that the Wyze Thermostat controls the Aux & Emergency Heat. Aux Automatically or Emergency Manually.

If connected to the " W1 " lug on the thermostat, it will control the backup as Aux Heat Automatically and turn it on if the heat pump can’t achieve set temp (+ differential) within 30 minutes or if the temp delta between the measured temp and target set temp is +5°.

If connected to the " * " lug, it would operate the backup manually as Emergency Heat, but there are drawbacks to this mentioned :point_down: below:

If jumpered, it could theoretically be used in both situations, but would need to be tested to confirm.

But, both must be specifically designated when doing the wiring setup on install.

@speadie would be best to verify my understanding of this though as it was their post that brought me to this conclusion. Because the OP had electric EH, it may be different and Speadie is the expert here.

W1 would have it operate automatically, “*” has it operate when emergency heat is on. but the wyze’s implementation of emergency heat is rather poor, it appears to disable the thermostat’s temperature control and it’s just an on or off switch.

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So I have them designated backwards above. The W1 is the automatic timed Aux and the * is the emergency heat with the caveat that when activated in the app it disables the temp control until deactivated in the app?

From my understanding, yes. I don’t have a heat pump to test this with, but from helping numerous people with their setups, that’s what I’ve gleaned.


Thank you so much for the assist and all the expert help you provide here in the forum! You are a valuable asset to the team!

Editing above to make it accurate.


I really appreciate the feedback on this topic!

I’m a little concerned about changing the wiring…

I haven’t seen a control for manual Emergency Heat in the app. Is that something that appears in the app if you wire it for that?

Is there any chance Wyze will do something to improve automatic functionality? It’s a total waste to run the Heat Pump in freezing weather. I’m concerned about my Electric Bill!

I believe the Emergency Heat UI only appears after it is set up on install.

Here is a post w\ pics of of what it looks like in the app:


Thanks for adding to this topic!

You mentioned “manually turning aux on…”
How did you do that?
I’ve not seen that in the app…

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Can Wyze officially confirm what parameters kick the aux heat on? Is this documented anywhere?

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I’m glad you brought this up!
I really like Wyze products, but this is a concern.
I appreciate the people that have contributed to this thread but I’m afraid to experiment with unofficial wiring.
I really don’t know what to do!
I’ve seen Wyze make improvements to their products… I hope they can improve this, or at least give me an official workaround.
Our electricity usage is up 250 kWh from last year… and the really cold weather hasn’t even kicked in yet.

I would like to see this as well. Also, in Oregon, to get a rebate for installing a heat pump, you have to be able to lock out the aux heat when the outside temp is above a certain temp (e.g. 40 degrees). I don’t see any way to do that.

Okay… For the record… We are in the single digits today (like a lot of people)… 5°F and my system still trying to use the heat pump.
If I bump the setting up about 10° warmer than what I want… it seems to go to aux heat. When it gets to the temperature I want, I have to turn it down to cooler than I want, which will turn it off. If I don’t turn it off… the heat pump will kick in again and blow cool air into my house.
So basically I have to watch it all the time… I’m the thermostat.

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Wyze is never going to address this. It’s been over a year with several LONG threads about this.

Over the weekend we had to put our old thermostats on because it was so cold outside. The Wyze tstats were just running and running and running. There are three huge issues that I am aware of;

Temperature sensor is broken. It will read “74” for example, while heating to 75, and just run forever and ever. If you manually shut it off or bump the temperature down, after a few minutes it’ll read “76”. So it’s been running for hours, but had actually reached temperature already. That’s one major issue.

Second - heat strip comparability is just weird. Sometimes they kick in after 30min, sometimes never, sometimes if you bump the temp up over 5 degrees.

Heat pump compatability is awful. My electric usage went up by 3x last month. And over the weekend when it was in the teens, our usage for that one day it was super cold and windy was over 300kwh. For one day.


Last months electric bill was over $500 and this is purely from Wyze running the system all day and night. I have a feeling next month is going to be worse, unless we take this off the walls.

Just for clarity - when I put the old tstats on, the heat kicks on with heat strips as it should, and satisfies the temp within an hour on those cold days. With Wyze tstats on the wall, it’ll run and run and run even though the temp has been ACTUALLY SATISFIED - it’s reporting the wrong temp and just won’t shut off when it’s cold. This causes a MASSIVE spike in electricity usage. BUT when you turn it off or bump the temp down, it’ll then read the correct temperature…meaning it should have shut the system off hours ago. Lmaooooo. Toss the old tstat on, and it’ll cycle normally. This is just so ridiculous at this point.

MOD NOTE: Post edited to conform to the Community Guidelines.

Amen, agree 100%. Same here electricity usage went through the roof with these units. Reinstalled my old thermostats and even thought the recent cold spell my system was able to hit temps with way less heat strip usage.

Officially returning both of my wyze thermostats.

It’s just bugged out.

Here’s the other side of the coin…right now currently, it’s 74 in the house. Heat is on to 75. For whatever u godly reason Wyze won’t activate the strips, so the heat pump is just running and running for hours trying to get to 75.

The kicker? It’s actually 75 in here. If I knock the temperature back to 74, the system will shut off and Wyze tstat after a minute or so will read 76. So it was actually at temperature the entire time…but the system is just running ALL DAY LONG.

This happens when it’s 25-30 outside. If it’s above 50-60, Wyze tstats work just fine most of the time.

I would think, this wouldn’t be that hard of a problem to solve. It’s just a software issue as far as I can tell.
Maybe I’m just not looking in the right place for an answer.
I noticed the moderator took time to edit one of the previous comments… but didn’t have time time give us any information on the subject.

@SlabSlayer Where are you reading this? (the logic and differential temps for aux heat)

I have a geothermal heat pump, meaning things work fine at 0F and below as my heat source is the ground. It’s the Aux heat coming on that causes my bills to go up. WIth the Nest and EcoBee you can set the differential temperatures for aux to kick in, they default to I believe 2.3F and my existing honeywell kicks in at 2F, both too aggressive power wise IMHO.