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Can You Install a Honeywell Thermostat Without Turning Off Power?

Last Updated Nov 2, 2021
Tech repairing a thermostat

Since devices like thermostats require a stable supply of power to properly operate, they need to be hard-wired into your home, including Honeywell thermostats. This drives many homeowners to wonder whether or not they need to turn off the power when installing a Honeywell thermostat.

You do need to turn off the power when installing a Honeywell thermostat. Honeywell provides exceptional directions to assist the homeowner in the installation process. This is done to avoid injury to the person and prevent damage to the device itself.

There are many Smart Home devices you can install on your own without turning off the power, but that doesn’t include Honeywell thermostats. For all you need to know on turning off the power when installing a Honeywell thermostat, keep reading.

Why Turn Off the Power When Installing a Honeywell Thermostat

Remember, you’re working with wiring, so this is a necessary step here before you even start to think about possibly not turning off the power when installing a Honeywell thermostat.

The obvious hazard with not shutting the power off is due to the possibility of electrical shock. 110 or 220 volts poses a serious safety risk and is not worth attempting with how simple it is to shut off the power to the device. Another risk associated is due to the potential damage to the device itself. In addition to the device being damaged, the wire could short out, or a fire could occur.

Does A Thermostat Need Power to Work?

Home thermostats are by far the easiest method to keep their homes comfortable no matter what the weather outside may be. They have evolved from being very straightforward devices to those that include full-color screens and Wi-Fi connections. Honeywell has been manufacturing these devices for over 100 years, and the company still adds new features and innovations as time goes on.

While all thermostats need some power to work, some require more than others. Older, more traditional thermostats obtain all the power they need directly from the furnace itself. As a result, these tend to have many fewer functions than the newer style devices. Wi-Fi-enabled units require a constant power supply requiring specific wiring and sometimes even batteries to assist.

The C-Wire

On almost all Honeywell Smart thermostats, a C-wire is needed to operate. The ‘C’ in this case stands for consistent. This means that the device is getting a constant supply of electricity to operate properly. The need for the constant supply of power is precisely why it needs to be shut off during installation; there is an ever-present risk of problems if left on while installing.

The end-user can look for this C-wire by removing the thermostat from the wall by gently pulling it straight out or removing fastening devices depending on the model. If the plate has a terminal marked “C,” constant current is going through and needs to be shut off. If there is not one, the installation instructions provided earlier can guide you through working around it.

How Do You Turn On/Off the Honeywell Thermostat?

Some references go so far as to recommend shutting off power to the entire house. All the installer needs to do is ensure the power going into the HVAC system is off. In either case, the device obviously cannot function without electricity and should start back up as soon as the power is restored.

Some older systems have a simple on/off switch on the furnace itself. These are usually the simplest of thermostats. On the newer, more feature-packed devices, flipping the breaker to the HVAC is required to ensure there is no potential for injury. In doing this, the power is removed from the furnace, the thermostat, and the air conditioner (if there is one). 

Always Double-Check

There is one main way to be completely sure if the power is off. On devices lacking a digital screen, you can attempt to adjust the temperature manually. If the HVAC system has not kicked on after a short amount of time, the power is off. If the device does have a digital screen and the screen is off, there is no power to the device, and the installer is good to continue.

Final Thoughts

The full line of Honeywell Thermostats is sure to contain something for a homeowner looking to upgrade, and in every installation scenario, the power should be turned off before installation. It is a matter of personal safety for the installer and to ensure the device does not get damaged in the process.