How To Install A Smart Thermostat

Just bought a brand new smart thermostat and wondering how to install it? It’s much easier than you think - just follow this guide and you can manage it yourself without hiring an electrician.
How To Install Smart Thermostat

Table of Contents

If you’ve just got yourself a new smart thermostat, you might want to consider installing it yourself rather than hiring a technician. Sure, installing a smart thermostat yourself requires some basic electrical wiring, but the average person can usually get this done with the right guide.

First things first, you need to make sure your thermostat is compatible with your current system and electrical wiring.

A great way to check this is by using compatibility tools online to check whether the smart thermostat you have is compatible with your current wiring.

It also helps if you dedicate a time to replacing your thermostat when a running HVAC system is important, such as during brutally cold winter days or when it’s really hot during summer. 

This is because you’ll have to shut off your HVAC system during the installation, and you don’t want to rush things just so you can have everything work again.

Also, it’s a good idea to keep your old thermostat just in case if you mess things up or can’t get the new smart thermostat to work – that way, you always have a backup option to  reconnect the old one.

Lastly, make sure you have a few tools around, such as a drill, screwdriver, and pliers.

On that note, let’s get started with our guide on how to install a smart thermostat.

How To Install A Smart Thermostat

1. Shut down your HVAC system

This comes at no surprise, you’ll need to turn off your HVAC system at the breaker panel – keeping in mind your system might have multiple breakers.  This is important to cut power to your thermostat and prevent you from shorting electrical components when working with the thermostat wires.

Locate your circuit breaker panel, then look for breakers that are labeled “HVAC,” which sometimes also say “heating and cooling”.  Flip them to cut off power to your thermostat and the HVAC system down.

If you have an old, battery-powered thermostat, it might still appear to be on even though the power is cut.

If this is the case, try turning the system on at your thermostat and keeping an eye out for signs of your system running to ensure that it is properly turned off. 

2. Remove the Faceplate

Next, remove the faceplate of your old thermostat to access the low-voltage wiring and backplate. For most models, this should pop off with a little bit of effort. Don’t force it if it doesn’t — instead, look for hidden screws that you might need to remove first, usually underneath the faceplate. 

If you still can’t figure out how to remove the faceplate, try looking for your existing thermostat online, and check to see if there are any specific steps to remove it.

Be sure to take a photo of the wiring to record which lines connect to which terminals. Certain thermostats also include stickers to indicate the wires with the codes on the terminals. 

3. Remove the Backplate

For the next step, remove the thermostat wires from the backplate. You might need to remove some screws that secure the wires in place, or depress small tabs using a pen to undo the wires.

As for the backplate itself, you should be able to use a screwdriver to remove the screws holding it on the wall.

Now would be a good time to take another picture of the wire positions and any labels from your old thermostat, which can serve as a good reference later. Make sure your photo shows the small letter labels on each connection and each wire’s color.

These wires are usually held by screws or tabs. Delicately detach these and remove the wires. Should the wires become disheveled, you can safely twist the wires together again for the new thermostat.

A note of caution here: If the existing wiring looks visibly damaged or very frayed, you might need an electrician to replace the wires.

Once the wiring is undone, simply remove the old thermostat completely from the wall. Most mounts for thermostats are typically screwed on and can be undone easily with a screwdriver.

After this, you should see a small hole with several wires coming out from it, and a patch on the wall where your old thermostat used to be. If it’s dirty, you can take this opportunity to clean the patch underneath your old thermostat. 

4. Install a C-Wire (if needed)

If your system already comes with a C-wire, you can disregard this step. If it doesn’t, you will need to add an additional wire to serve as the common wire, which provides power to the thermostat.

If you didn’t know, the  C-wire is the most common way to provide power to your smart thermostat.

Several thermostat manufacturers, like Ecobee, throw in an adapter with their smart thermostats to add a C-wire.

Another option would be to purchase and install a third-party “add-a-wire” adapter. These adapters will come with instructions, and it is recommended to follow them properly.

Installing a common wire could risk damaging your system if not done correctly, so if you’re not comfortable doing this for whatever reason, do consult some help from an electrician. 

5. Attach the New Backplate

For the next step, you’re going to attach the new mounting bracket to the wall. It’s important that you center it precisely so the wires coming from the wall are centered on the new mounting bracket.

Also, ensure that the mounting bracket is level – some thermostats even come with a built-in level.

As smart thermostats don’t weigh much, you won’t need to drill into a stud or use drywall anchors.

With that said, if your system does ship with drywall anchors or if the instructions recommend using them, then do it.

After all that is done, just screw the new backplate in place. Gently pull on the wires from the wall outwards through the backplate before screwing it into the wall. 

6. Reconnecting Wires

After the backplate is secured, it’s time to reconnect the thermostat wires to their corresponding terminals.

This step should be pretty straightforward, especially if you have the photos you took earlier to refer to.

7. Install the New Faceplate

With the wiring done, you’re almost done!

Now, you should be able to easily snap the faceplate of your new smart thermostat onto the backplate. If it doesn’t attach easily, don’t apply force since some wires could be in the way. In that case, try tucking them back into the wall before trying to attach the faceplate again.

With the new faceplate installed, you can now turn on the breaker for your HVAC system again. This power to the thermostat, which will start up for the first time.

8. Connect to WiFi

With your new smart thermostat powered on, you’ll likely need several prompts to connect it to WiFi and set up its companion smartphone app. This part differs depending on the smart thermostat you have, but generally, they’re all relatively straightforward to set up.

It also helps if you have your WiFi password on hand, as you’ll need to enter this into the smart thermostat for it to connect to your WiFi network.

After connecting to WiFi, try using your brand new smart thermostat to adjust your home temperature to check if it works. If it does – you’re good to go!


Most of us are looking to purchase a smart thermostat to save money on energy costs, which is a great long term investment. However, as we’ve seen from this guide, you shouldn’t need to pay extra to hire someone for installation!

Installing a smart thermostat isn’t that hard, and can be done by the average person with just a few tools. Just be sure to follow the instructions exactly and avoid mistakes that can damage your system. 

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