How to Replace a Honeywell Thermostat
Brad Pretty, 2 years ago   |    15   |    3 min read   |    20462

Honeywell thermostats have become the standard for basic thermostats in homes with all sorts of heating systems, especially baseboard heating. The name has become ubiquitous with any of the simple dial thermostats, even if they were manufactured by an array of different companies. If your heating was installed any time in the past 20-30 years, there’s a very high chance that it’s controlled by an analog Honeywell thermostat.

And it’s time to upgrade.

But upgrade to what? Well, we’ll get to that in a second.

Steps For Uninstalling

Whether it’s a broken thermostat, an upgrade, or a replacement, let’s get that old thermostat off your wall safely.

First rule of changing a thermostat: turn off your breaker.

Second rule of changing a thermostat: Turn. Off. Your. Breaker.

Check and double check that there isn’t any power surging through your lines before you go ahead and do any work on it. There won’t be any indication on your thermostat, so have a voltmeter handy. If you don’t have one, your best bet is to turn up your thermostat and wait 20 minutes. If your heater doesn’t respond and is cold to the touch, you’re ready to move onto the next step:

Remove the faceplate and unscrew the thermostat from the gang box.
(You may run into some trouble getting the faceplate off the wall, especially if it’s old and has been painted over. Just use a knife or something similar to gently pry it off.)

The thermostat should fall loose now and you should be able to see the wires.

Carefully separate the wires that attach the thermostat to the power source.


TA-DA! Your thermostat should come off with ease.

Now that the thermostat has been removed, you’re going to have to make a decision for a replacement.

The two main options for upgrades: Programmable and smart thermostats.

Now that you can see the wires in your gang box, let’s see if you’re compatible with Mysa. Use our compatibility checker here to find out!

What to Switch to?


The first step up is a programmable thermostat. These have been around for a couple of decades now, but are gradually starting to show their age in favour of more advanced, user-friendly technology like connected, smart thermostats. While programmable thermostats will help you maintain a steady schedule, they offer little in the way of advanced control that or technology that will further supplement the amount of energy you can save.

Having a set schedule seems nice, but the statistics tell a different story: only 30% of all programmable thermostats are actually set to a schedule at any given time. Why is this? Is it the overly complicated nature of setting them up? Their inaccuracy? Or a combination? Doesn’t matter – the point is that programmable thermostats are becoming obsolete in the age of the Internet of Things.


Smart Thermostats have become the most sensible, cost-effective, and ahead of the curve way to control the heat in your home. For most forms of home heating, a smart thermostat will give you unparalleled control and will benefit you greatly compared to simply replacing it with another “dumb” thermostat or even a programmable one. Any extra upfront cost will be quickly seen in the savings they provide, the ease of use, and the overall usefulness of all the smart features.

Want a schedule, like the programmable thermostats? Done – and might I add, in much less time. Or you could simply go with geofencing and allow your heat to cut in only when you’re on your way home. Makes everything more flexible, easy, and accommodating for the modern household.


  1. Scott

    Do I need a new thermostat for each zone if I’m going with the smart Mysa

    1. Rebecca Collins

      Hi Scott,

      The short answer is yes! And if you have multiple Mysas, you can actually link them together in your app into 1 Zone so that 1 command goes to all of them. I hope that helps!

  2. Richard

    What if there are two baseboards on the same line? Let’s say a 2000W and a 1500W. Can one thermostat control two heaters if on the same line? Total watts are 3500 max?

    1. Brad Pretty


      That theoretically should work! Check with out support team at to verify.

  3. Angie Killian

    So the article says “Now that you can see the wires in your gang box, let’s see if you’re compatible with Mysa. Use our compatibility checker here to find out!” and yet I see no sign of a compatibility checker … I think I need one, because my last thermostat only has two wires going into the wall, and this one has four?! Help?!

    1. Brad Pretty

      My mistake on the missed link. Here’s our compatibility checker:

  4. Hoss

    Hi. I need a smart thermostat for baseboard heaters and a smart lock. Based on my research mysa is the way to go with baseboard heaters. What are your thoughts on the systems that integrate thermostats and smart locks. TY

    1. Brad Pretty

      Mysa is compatible with a range of home automation systems, so my advice is to make sure that whatever smart lock you choose is also compatible with one of those systems! (ie. Google Assistant, Apple HomeKit, Amazon Alexa).

  5. Anna S

    I have 11 different thermostats…one in each room of my home. Is there a way to have a master thermostat in three of the rooms and have others receive a signal to mimic what the master is doing? Having to buy 11 fully programmable units seems like an expensive undertaking.

    1. Brad Pretty

      Unfortunately, there isn’t because of the nature of electric heat.

  6. Guillaume

    I tried different configurations in the compatibility checker, but none of them give me a compatible one. I have a baseboard heater that is controlled by such an honeywell thermostat.

    1. Brad Pretty

      You can get in touch with our support team at

      They’ll likely want to see pictures of the wiring and help you from there!

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  8. Jenny

    I have 240V electric baseboard heat – can I use a line voltage Mysa thermostats in my home, or is this too “high voltage” for that?

    1. Alexander Chafe

      Hey, Jenny! Sounds like you may be compatible, however, we suggest completing our online compatibility checker to confirm that your wiring is compatible with our product and that your total wattage doesn’t exceed 3,800 watts:

      If you have any questions along the way, feel free to reach out to our customer experience team at and they would be happy to help you out 🙂

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