Get a new smart thermostat? We understand if you don’t want to pay extra to have it installed professionally when you can do it yourself. Installing a smart thermostat requires some basic electrical wiring work, but the average homeowner can usually tackle the task with the right guidance. Learn how to install and operate your smart thermostat here. Here are some helpful tips and tricks you should know.
Note: A screwdriver, drill bit, and needle-nose pliers are important tools you may need.
Step 1: check HVAC compatibility
Ideally, everyone should check the compatibility of their HVAC system before even buying a smart thermostat. Not all smart thermostats are compatible with existing wiring, depending on what type of system you have (heat pump, stove, etc.) and how the previous thermostat was wired.
Fortunately, Google has an excellent compatibility tester for their Nest thermostat. We encourage you to visit him and go through the steps to check your wiring. This compatibility test should work for most other smart thermostats on the market as well.
Pay special attention to wire quality and tension, which can be an issue for smart thermostats. Smart thermostats usually require a C-wire for continuous power supply, which is common in modern homes but is not guaranteed. C-Wire adapters are also available. However, if you don’t have a C-Wire, we recommend contacting an electrician to have one installed. Google’s introduction of wire labels will come in very handy later when installing a new thermostat. This is a great exercise even if you’re pretty sure your smart thermostat is compatible.
Step 2: Turn off your thermostat and access the thermostat wiring
Find your breaker bay and look for breakers labeled “HVAC” or sometimes “Heating and Cooling” (there may be more than one breaker). Turn them off to turn off the thermostat and shut down the system while you work.
If you go back to your thermostat and it’s still on, a battery backup may be in place. As a test, try to change the temperature significantly and see if your HVAC system turns on.
When the power is finally off, remove the faceplate of your old thermostat if you haven’t already done so in the steps above. The faceplate usually loosens when you pull on it, although sometimes a small screw or fastener holds it in place. So, carefully review the design. If you can’t figure out how to remove the faceplate, search for your thermostat model online and see if there are specific instructions.
Once the faceplate is removed you should see a number of wires connected to various terminals on the thermostat.
Step 3: completely disconnect the old thermostat
Stop and snap a smartphone picture of the cable locations and any labels for your old thermostat. This is not always necessary, but can be a very useful reference later. Do you notice the small letter labels on each connection? That is what you want to note along with the color of each wire. Take multiple photos if necessary, and if the wires aren’t crisp, separate colors, you can become You’ll need to put small tags on them before proceeding. Fortunately, not all thermostat wiring is as confusing as the one shown above. Many have simpler configurations like this:
These wires are usually held in place by tabs or screws. Carefully loosen these and remove the wires. If the wiring looks a little disheveled, you can twist the wires back together in preparation for the new thermostat. If the wiring looks badly damaged or badly frayed, if you are inexperienced in repairing wires, consult an electrician.
With the wiring disconnected, you can now completely remove the old thermostat from the wall. The bracket is usually screwed on and can be unscrewed with a screwdriver if necessary. What is left should be a small hole with a bunch of wires and a blank spot on the wall. Clean the wall if it is dirty under the thermostat.
If your smart thermostat is smaller than the old model, this is also a good time to paint the wall below if the wall colors don’t match (this is why it’s handy to keep a can of house paint in stock).
Step 4: install the smart thermostat bracket
If you haven’t already, unpack your smart thermostat, remove the pieces, and find the bracket – sometimes called the trim panel or just the back panel (the trim panel may be a separate piece, but it’s a good idea to install them as good). These are also designed so that they can be screwed into the wall. Feed the wires through the bracket and secure them in place. You may be able to use the old screw holes if they are properly aligned. Otherwise, mark and drill a new hole for this operation. If old holes are still visible, you can always patch them later.
One advantage of smart thermostats is that their cabling mounts are very clearly labeled and well designed. Above is an example of the Nest Thermostat Mount. Below is an Ecobee 4 thermostat bracket.
You will see the slots and tabs for attaching individual wires in the correct order. Now is the time to focus on the details.
Step 5: Connect the wiring to the Smart Thermostat
This step will depend on the wiring of your old thermostat. If the wires are in good condition and labeled on the wiring itself, you can easily attach the wires to the appropriate tabs on the bracket. Make sure each wire is fully inserted and secured before proceeding. As you can see, needle-nose pliers can help direct and cram wires as you work.
If your cables don’t have labels, now is the time to go to your smartphone and look at the photos you took of the old cables so you can match the color of each cable to the correct tab.
Step 6: attach the smart thermostat faceplate
When all the wires are in place, carefully insert them into the bracket. Now attach the “front panel” of the smart thermostat, which is usually more of a computer with a monitor attached. The faceplate should of course snap into place on the bracket as long as there are no wires in the way. Make sure it’s level and not upside down – round thermostats like Nest should also be installed correctly.
Step 7: Turn on your Smart Thermostat and connect it to Wi-Fi
Now you can start the installation on the software side. Go back to your breaker bay and turn the power back on for the HVAC system. Check your smart thermostat: it should now turn on and boot up. When you’re done, the thermostat should walk you through a few basic steps to connect to your home WiFi network. So have your WiFi name and password ready. You should also be able to do this directly from the thermostat app, which you should download now if you haven’t already.
After connecting the thermostat, you can choose a number of settings to heat and cool your home. Follow the instructions in the app / thermostat to adjust your temperatures, the behavior of the thermostat and the information displayed. You are done now. It’s a good idea to explore unfamiliar smart features in the days to come so that you know how they work and how you can take advantage of them.