Shut Off Power
Before any thermostat installation begins, turn off the power to the furnace or the circuit breaker to the existing thermostat; these are safety precautions. It’s extremely important to ensure the power is off. If unsure which breaker powers the thermostat, the best option is to run a few power tests or to shut off the main breaker completely as a failsafe.
While most smart thermostat installations are pretty standard, some brands may deviate from the standard process. Be sure to read through the manufacturer’s manual before beginning. And remember, always consult or hire a licensed electrician to answer any questions.
Remove Thermostat Cover
When removing the old thermostat, start by removing the cover. Normally the cover pops right off, however, it may require removing some screws.
Removing the faceplate will expose the low-voltage wiring. Before the technical part begins, have the thermostat instructions available. Some instruction manuals are easier to understand than others, for example, installation instructions for the Google Nest Thermostat are illustrated for easy comprehension.*
*FirstEnergy Home’s review of this product is solely opinion. FirstEnergy Home did not receive compensation for the review. FirstEnergy Home, and any FirstEnergy affiliates, are not affiliated with the manufacturer of the product, nor is there any endorsement or sponsorship between the product manufacturer of the product and FirstEnergy Home or any of its affiliates.
After removing the cover and gaining access to the wiring of the old thermostat, it’s time to disconnect. It’s important to take a picture of the existing connections or to label the wires and corresponding terminals. Remove the screws that hold each wire in place, then gently pull the wires from the terminals.
It’s true that it is not difficult to install a smart thermostat, but working with electrical wires can be confusing. If this type of installation is uncomfortable, consider a licensed professional.
Remove Mounting Plate
After disconnecting the wires, remove the mounting screws. This will allow the mounting plate to be unattached from the wall. Now that the components of the previous thermostat have all been removed consider using tape to hold the wires in place so the wires don’t fall back inside the wall.
Old thermostat designs are fairly different from the smart ones used today, so there’s a good chance the new thermostat won’t align with the existing holes in the wall. In order to create new holes, remove the anchors from the old holes and then patch and repair the drywall as needed.
Attach New Mounting Plate
After removing the wall anchors and patching, place the new thermostat on the wall and mark the mounting holes, but remember to make sure the marks are level. After marking and leveling, screw in the mounting plate.
Remove the tape from the wires and pull them through the opening of the mounting plate. At this time, consult the owner’s manual for any additional steps specific to that thermostat model.
Attach the wires to the correct terminals of the new thermostat. At this point, you may notice whether a C wire is present. The C wire is not mandatory, but it’s often recommended and can affect the use of some features if not present. If the C wire isn’t present an adapter may suffice.
Once the connections are in place, double check that all wires are secure. Again, working with wires isn’t for everyone and a licensed electrician or HVAC professional can finish the job if needed.
Add New Thermostat
Attach the smart thermostat faceplate to the mounting plate making sure there are no obstructions. Some thermostats may require a battery, so make sure to add if needed.
Turn the Power On
It is now safe to turn the circuit breaker back on. The thermostat should be working. At this point in the installation process, another general question may be ‘how to connect a thermostat to Wi-Fi?’
Every smart thermostat includes instructions for connecting the device to Wi-Fi. For wireless control, download the thermostat app onto a mobile device. This will allow for mobile control of all features.
The smart thermostat installation is now complete. If you would like to learn more about smart home devices, please browse other articles in the Learning Library.
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1Consumer Reports. How to Install a Smart Thermostat. Retrieved from How to Install a Smart Thermostat (consumerreports.org)