Programmable Thermostat for Heat Pump with Emergency Heat (Smart Home Compatible)

jschoenbaechler@gmail.comreviews11 Comments

Programmable Thermostat for Heat Pump with Emergency Heat (Smart Home Compatible)

If you are looking for a new thermostat for your heat pump with emergency heat, you are in the right place.  It can be confusing to find a smart programable thermostat that easily works with emergency / auxiliary heat and has advanced functions like scheduling and smart home integration.

The Sensi Touch Wi-Fi Thermostat by Emerson was my choice.  Scroll down for all the details on the Sensi and another premium option, or keep reading for an overview of the key features and functions to look for when choosing a smart programable thermostat.

Why did I need to find a new thermostat?

My parent’s have a condo in Florida that’s not used for several months out of the year.  They wanted to upgrade their thermostat, so the temperature could be monitored while they were away.  You would think any smart thermostat at your local big box store would be up to the job, but many of them either don’t work with emergency heat or are difficult to enable.  The search ended with 2 prospects the Sensi Touch Wi-Fi and the Nest Learning Thermostat.

What is Emergency Heat and Auxiliary Heat on a Heat Pump

Heat pumps function like an air conditioner, in fact in many cases the same unit works to heat and cool you home.  Since heat pumps are just transferring heat from the air outside your home to the inside, instead of burning fuel they are very energy efficient.  If you’re interested in learning more about how heat pumps work check-out this article on how stuff works.

As the outside temperature gets lower a heat pump has less heat it can “move” into your home.  At some point the heat pump can no longer keep up with the demand for heat.  This is where Emergency or Auxiliary heat comes in.  An electric furnace coil in your air handler can be turned on during these low temperatures to meet the heating requirements.  You can check out this article for more information on the difference between Emergency Heat and Auxiliary Heat.

Smart Thermostat Features and Functions

In addition to setting your thermostat to a single mode and temperature, modern thermostats can do much more to make you more comfortable and save you money.

Scheduling and Geofencing to control temperature

The best way to save energy on heating and cooling is to set the temperature back at night or while you are away from the home.  This will save you from heating or cooling an empty house.

When to choose Scheduling

Do you go to work and come home at the same time every day?  If the answer is yes, then scheduling is probably a great way to go.  You can program your thermostat to set the temperature back right after you leave and resume your desired temperature before you get home so the house is comfortable when you arrive.

Usually schedules can be setup for each day of the week, so your Monday, Wednesday and Saturday schedules don’t have to be the same.

Another reason to use scheduling is if you don’t have a reliable connection to the internet.  Once a schedule is set it will continue to work even without a connection.

When to choose Geofencing

Geofencing works great if your schedule changes from and week to week.  If you never know when you will be home geofencing allows your thermostat to change the temperature based on your location.  This works by using the location services on your smartphone.

Automatic Adjustment (learning)

Nest created the Learning thermostat.  The advantage of a learning thermostat is that it will learn your routine as well as how your heating and cooling systems respond.  Then a learning thermostat will automatically adjust the setpoints (within a predefined range) to maximize comfort or efficiency.


One must have feature is Wi-Fi.  This is what allows you to remotely access your thermostat and what allows integration with third party smart home equipment.

Remote Control via Smartphone App or Web browser

Most smart thermostats have a smartphone app or web interface, but there are some features you should look for.  Check to make sure your thermostat is compatible with Android and iOS as well as Mac and PC web interfaces.


  • Monitor current temperature
  • Monitor Humidity
  • Change Setpoint
  • Change Heat / Cool / Auto Mode
  • Change Fan Mode
  • Change Schedule
  • Alerts (via app or email)
    • High / Low Temp
    • Malfunction
    • Humidity

Smart Home Compatibility

Having the ability to integrate with other smart home systems allows you to do even more to improve the comfort convenience and safety of your home.

The some of the big smart home platforms are:

  • Wink
  • Amazon Alexa
  • Samsung Smart Things
  • Apple Home Kit
  • Google Home

You don’t need to be compatible with all of them, but choosing 1 and buying equipment that can be integrated together in the future is a good idea.

What can you do with a smart home integrated thermostat?

Here are a few examples of ways to integrate your thermostat and other smart home devices

  1. Energy Efficiency – Automatically setting your thermostat back when you arm the security system is a great way to save energy without setting up schedules.
  2. Safety – Stopping your HVAC system when a fire alarm goes off will stop smoke from being pulled into more rooms of the home through the duct work.
  3. Comfort – Telling a virtual assistant like Alexa to turn on entertain mode could set lighting, music and adjust the temperature in your home to get ready for your guests to arrive.

Best Programmable (Smart) Thermostat for Heat Pumps with Emergency (Auxiliary) Heat

Budget Option – Sensi Touch Wi-Fi Thermostat

The Sensi thermostat is a great all-around thermostat that checks all the important boxes when it comes to features and capabilities.  While this is my favorite model for heat pumps with aux heat, it is also a great option for other types of heating systems like fuel burning furnaces and radiators.  In addition to monitoring the temperature in your home this thermostat will also shoe you the relative humidity on the display and it’s smartphone app.

Sensi Touch Wi-Fi thermostat

Click here to see the current price for the Sensi Touch Wi-Fi Thermostat on Amazon

Features and Specs

Systems compatible with the Sensi

Heating 1 and 2 stage
Cooling 1 and 2 stage
Heat Pump Yes, with Auxiliary and Emergency Heat
Accessories None
Fan Yes
Power 24 VAC



Length 5.6”
Width 3.4”
Depth 1.1”
Weight 8.6 oz
Colors Black


Smart Home Functions

  • Geofencing
  • Scheduling
  • Remote Access via App and Web Browser
  • Integration with Amazon Alexa, Apple HomeKit and Wink

Will Sensi work with your wiring?

The Sensi thermostat works in most standard situations.  The best way to find out is to use the interactive tool on their website.  After looking at what wires are connected to your existing thermostat visit the wire picker on the Sensi site.

Click here to open the wire picker

Installation Process

Installation of the Sensi Touch Wi-Fi thermostat is simple.  My dad installed his in about 30 minutes.

Thermostat for heat pump with emergency heat

Thermostat for heat pump with emergency heat

Sensi Touch Wi-Fi thermostat before installation

Sensi Touch Wi-Fi thermostat before installation

Step-by-step instructions on the App

I won’t cover the installation steps, because the Sensi App does a great job with that.  Once you download the App, available for Android and iOS, you will have an illustrated guide that walks you through each step of the process.

One thing I will point out is the included wire labels are great.  This way you won’t forget which terminal the orange wire came from.  Just label each wires as you remove them from the old thermostat.

sensi thermostat wire labels

sensi thermostat wire labels

Sensi Installation Video

How does the Sensi Thermostat work with Heat Pumps and Auxiliary (Emergency) Heat?

Sensi Touch Wi-Fi App Modes

Sensi Touch Wi-Fi App Modes

Reading the specs and manual doesn’t clearly explain how the Aux heat functions.  After a short phone call with a technical support representative at Sensi I found out exactly how it works.

The thermostat has 4 modes of operation:

  • Cool
  • Heat
  • Auto
  • Aux Heat

We won’t worry about cool because all heating functions are disabled in cool mode.

Auto and Heat Modes

When the thermostat is set to auto or heat mode the primary heat source will be your heat pump.  If the heat pump cannot reach the desired temperature the auxiliary heat will be turned on automatically.  The heat pump and auxiliary heat source will operate together until the temperature is reached.

Aux Heat Mode

If you select Aux Heat Mode the heat pump is turned off and the only heat source is your auxiliary heater.  This mode should only be used if the heat pump malfunctions or if you need to take it out of service some other reason.

Using the Sensi Touch Wi-Fi

How to adjust the Sensi Thermostat

There are 2 ways to adjust the setpoint mode and other features of the thermostat.  Each method as a slightly different set of features.  For Example, schedules cannot be set on the thermostat itself.

Creating Schedules with the Sensi

Schedules can be created within the Sensi App.  Schedules can be created for Cooling, Heating and Auto modes.

sensi app schedules

sensi app schedules


Geofencing is enabled through the scheduling menu on the Sensi App.  Once enabled if you are more than 3 miles away from your home the thermostat will raise the temperature by 3 degrees if in cooling mode, or lower the temperature by 3 degrees in heat mode.

sensi app geofence

sensi app geofence

Can more than 1 device be setup with geofencing on the Sensi?

Yes, The Sensi thermostat allows you to add as many devices as you want.  If the app on the device is logged into your Sensi account and geofencing is enabled it will control your thermostat.  Just remember that if 1 logged in device is within 3 miles of the home the thermostat setpoint will not change.  So, don’t enable geofencing on your iPad that never leaves the home.

Upgrade Pick – Nest Learning Thermostat

We went with the Sensi because it did everything we needed, but you want a few more features and don’t mind spending a little more the Nest Learning Thermostat is the premium choice for a heat pump / aux heat situation.  Again, this is also an excellent choice for other HVAC systems.  Like the Sensi model the Nest thermostat displays both the temperature and humidity.

Click here to see the current price for the Nest Thermostat on Amazon

Features and Specs

Systems compatible with the Nest Learning Thermostat

Heating 1, 2 and 3 stage
Cooling 1 and 2 stage
Heat Pump Yes, with Auxiliary and Emergency Heat
Accessories Humidifier and Dehumidifier
Fan Yes
Power 24 VAC



Diameter 3.3”
Depth 1.2”
Weight 7.25 oz
Colors White, Black, Stainless, Copper


Smart Home Functions

  • Learning
  • Geofencing
  • Scheduling
  • Remote Access via App and Web Browser
  • Integration with Amazon Alexa, Apple HomeKit, Wink Samsung Smart Things and over 50 other brands.

Will Nest work with your wiring?

The Nest thermostat is compatible with even more systems than the Sensi.  After looking at what wires are connected to your existing thermostat you can use the Nest compatibility checker.

Click here to open the compatibility checker

Nest Learning Thermostat Video

What will Nest do that Sensi won’t?

The Nest thermostat shares many of the same features as the Sensi model.  So, what does it do to deserve the higher price?  Here are some of the most important advantages of the Nest.

  • Heat Pump Balance – This is the biggest advantage for heat pump owners. With the this feature you can choose between 4 modes.  This will even calculate and adjust your temperature setting at night to minimize your heating costs.
    • Max Savings – Most energy efficient, will only use aux heater when it’s needed to reach the desired temperature.
    • Balanced – Uses a combination of the heat pump and aux heater to heat the home quicker, while still keeping an eye out for efficiency.
    • Max Comfort – Always uses the auxiliary heater to heat your home as quickly as possible.
    • Off – Only uses the Aux heater when the outside temperature is below a lock out temperature that you define.
  • Learning – in addition to manually defining schedules and geofencing, the nest thermostat will learn where you want the temperature based on how you change the setpoint from day to day. After tracking your manual temperature adjustments, it will create schedules to match your habits.
  • Humidifier and Dehumidifier controls – With this thermostat you do not need a separate control for these accessories. You can set and adjust the humidity and temperature in your home all from the nest thermostat and app.
  • Nest Family of products – Nest also has a variety of products like remote temperature sensors that can be placed in other rooms. Smoke detectors that integrate with the thermostat and cameras for security that also help the thermostat learn your routines.


Either of these thermostats would be a great upgrade from a traditional manual thermostat.  Both options integrate with other systems, allow remote access and monitoring and allow you to schedule your temperature in a variety of ways.

The Sensi Touch Wi-Fi is a slightly simpler thermostat with a little lower price tag.

The Nest Learning Thermostat has some more advanced features to automatically adjust your heating and cooling save money on your energy bills, but you will pay more upfront.

Let me know which feature is most important to you and which model you pick in the comments below.  If you have any questions please leave them in the comments below too.

Thank for reading,


11 Comments on “Programmable Thermostat for Heat Pump with Emergency Heat (Smart Home Compatible)”

    1. Shaun,
      Unfortunately, I’m not sure. If I am able to check I will post an update.
      Thanks for the question,

  1. Hey Jason. Bob Sherman here. I live in Gloucester, Virginia. I have a Sensi thermostat installed for my hvac system. Yes.. The device displays when the Aux system is being used. My system is a dual heat system of a heat pump and a propane furnace. At cooler temperatures, the heat pump works just fine. At cold temperatures the propane furnace fires up. I called Sensi support to ask when the furnace kicks in. They responded there is a built-in algorithm to kick in the furnace when the heat pump can’t keep up with bringing up the temperature to the set point. I’ve tried to discover what that Outside temperature would be and discovered two things 1) If I try to raise the temperature by more than 5 degrees, the furnace kicks in. For example, raising the inside temperature from 65 degrees to 70 degrees, the furnace will kick in until it reaches 70 degrees. After it reaches that set point, the heat pump will maintain it. And 2) if the outside temperature is somewhere around 35 to 40 degrees, it stays on the auxiliary heat furnace. That algorithm must think there’s little heat in 35 degrees and doesn’t even try. Hope this helps.

    1. Bob,
      Thanks for sharing what you know about the Sensi thermostat.
      It’s great when readers help each other out.
      Thank You,

  2. The Nest will not work with a dual fuel system unless there is special wiring, but I cannot find anything on the Sensi. Will it work on a dual fuel? I have it installed in my house now but I am concerned I may have made an error.
    Thank you,

  3. Your article is okay. But, what about an American Standard heat pump with 2 stages of cool and 4 stages of heating with 2 stages of heat pump heating and an additional 2 stages of heat strip heating?

    2nd question: Why in the world won’t the thermostat m anufacturers have a customer service rep that respond to questions instead of just saying talk to your heat pump vendor — when most of the time the heat pump vendor is an installer and knows little about controllers?????

    1. Gonzalez,
      I don’t know too much about multi stage heating, so I can’t provide any help there.

      I think the problem with the customer service reps is that they don’t know much either. They have a list of common questions and answers, if your question doesn’t fit with their list they pass you off to someone else.


  4. The Nest is exactly what I’ve been looking for. The “ off “ will save lots of energy costs for me and anybody else that chooses to use it. I live in central Florida and like to sleep in a cool bedroom so I have no heat on at all 99% of the time while sleeping. I choose to start the heat pump when I get up in the morning . I choose to have no adaptive recovery or early start by the thermostat to warm the home before I get up in the morning. So the problem with my expensive Honeywell and any thermostats that I have read about is the emergency heat differential is not adjustable. So when I turn on my heat pump in the morning and raise the heat setting by more than 2 degrees the emergency heat kicks in wasting a ton of energy . This is happening in so many southern state homes of course without the homeowner realizing it. I think that this should be advised and explained in order to save energy. I understand that this approach would not be for everyone but I think that everyone should have this choice and be incorporated in all heat pump capable thermostats . Thank you, Ed

  5. Do you know if the Sensi will let you schedule heating on a specific source?
    For example, I want to use Aux heat at night (as my heat pump is noisy) and Heat pump during the day. Is that possible ?

    1. I don’t think that is possible directly from the Sensi app, but you might be able to do it with a 3rd party like alexa or smart things.

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