I Want a Smart Thermostat but Don't Have a C Wire - What Do I Do?

June 09, 2021

When you’re wanting ways to lower energy expenses, getting a smart thermostat is a wise move. These devices pick up on your temperature preferences and routine and then make an energy-efficient schedule that matches. What’s even better is that you can change and watch your settings from almost anywhere with your phone, whether you’re relaxing in bed or on the go. (You might even be able to get a free smart thermostat depending on rebate programs from your utility provider in Shelby.)

In many instances, hooking up a smart home thermostat with the assistance of Hopper Heating and Air is a straightforward task if you have a new home. But what if your house is older or doesn’t have the correct wiring? Can you still add a smart thermostat without C wire? We’ll help you demystify the process so you can pick the proper thermostat and enjoy energy savings for years to come.

What Is a C Wire and What Does It Do on a Thermostat?

The majority of programmable thermostats run on batteries. When you’re switching to a smart thermostat, you’ll discover that many require a C wire, or common wire, for power. If you don’t use this wire, your new thermostat may cause your heating and cooling system to have glitches.

You can determine if you have a C wire by doing the following:

  1. Cut power to the thermostat at the breaker.
  2. Take off the thermostat and check the wiring.
  3. If there are five or six multicolored wires, you have what you need for a smart thermostat. You might be wondering what color is the C wire on a thermostat—and the answer to that is often blue.
  4. If there are three or four thin multicolored wires, you’re close. Check the C wire isn’t hidden within the wall. If you can’t find one, we may be able to install one for you or you may be able to use your new thermostat without one.
  5. If you have two thick wires, you may be able to use a smart thermostat with an adaptor specifically for high-voltage systems. Or you may be able to install a battery-powered smart thermostat, like the Lux Geo Wi-Fi Thermostat, if your wiring won’t work and you don’t want to install new wiring.

Do Nest or ecobee Need a C Wire?

Two of the best-selling brands are the Nest smart thermostat and ecobee smart thermostat. If you have two to four wires, these thermostats might be an option for your needs.

Nest says its thermostats are made to require minimal power and can often share it with your home comfort system. However, you may need to have a specialist like Hopper Heating and Air add a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re experiencing power problems or a battery that’s frequently drained.

ecobee connects with 24-volt systems (ones with three to six thermostat wires) and comes with a C wire adaptor. So, you’re taken care of if you don’t have a thermostat C wire.

Depend on Hopper Heating and Air for Your Smart Thermostat Installation Needs

At Hopper Heating and Air, we’re always looking for methods to keep you cozier while keeping utility expenses reasonable. If you want to learn more about installing a smart thermostat without a C wire, give us a call at 704-233-7363. We can help you select the right model for your home and even add new wiring if required.