Thermo - Geothermal compatibility and energy savings

Looking at replacing my old Honeywell programmable thermostat

On the surface the Wyse seems compatible but some important functions don’t seem documented.

For example, on the Honeywell the AUX (electric) heat kicks in with greater than a 2F differential. THis isn’t very compatible with a programmable thermostat with regards to energy savings. The Nest and Ecobee allow you to set that differential and have multiple programs. I’m not seeing anything in the wyse documentation discussing differentials or if they are setable. This would be a deal breaker.

In addition, I’m seeing some discussion here of Wyse using internet weather to determine if aux heat is used. Since I’m Geothermal only the ground temp matters.

Really just looking to see if there is a level of documentation similar to their competitors so I can decide.

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I posted this as a new topic since it deserved it, but to wrap this comment up

I’ve seen a lot of guessing on the forums but I seemed to have gotten a definitive answer, abet I had to dig into the details. After quite a few go arounds with Wyze support as to the algorithms used in heat pumps and specifically geothermal I got this response. I bolded the relevant passages:

Hello Jeff,

Thanks for following up on this issue and apologies for the inconvenience this issue had caused you. I have raised your question to the team for further checking. Allow me to explain further.

I got an update from them that the Wyze thermostat does not distinguish between Air Source Heat Pumps and Geothermal Heat Pumps. The outdoor weather is used to determine when to run only the Aux heat in both cases. However, there are other factors that determine when to run both Aux heat and heat pump.

  1. When the temperature difference between setpoint and room temperature is greater than 4 F
  2. When the heat pump has been running longer than the default runtime (determined by Behavior settings - eg: max savings, balanced, max comfort, etc)

In summary, Geothermal Heat Pumps are compatible with the Wyze Thermostat but are treated in the same way as Air Source Heat Pumps.

I hope that answers your questions. Should you have further questions, feel free to let us know.


Jennifer | Wyze Wizard

This is good info with regards to the algorithm, but also discloses the Wyze is NOT compatible with GeoThermal heat pumps. Yes, it will control them, but the bill will skyrocket needlessly in the winter. A geothermal heat pump doesn’t work against the outside air as a standard heat pump, but against the earth’s temperature. So going to AUX heat based on ‘outdoor weather’ will needlessly increase the electrical bill on a geothermal unit.

This seems a easy fix, As the unit doesn’t have a outdoor air temp sensor, one would guess it gets the temp for your location from the internet. Wyze should either ignore the outdoor temp for geothermal or just set up a zip code on the equator.

Does anyone have access to the tech team or programmers? I’d really like to stay with Wyze as I need the indoor sensors.


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