I Want a Smart Thermostat but Don't Have a C Wire - What Are My Options?

June 09, 2021

When you’re seeking approaches to decrease energy expenses, upgrading to a smart thermostat is a smart decision. These devices pick up on your temperature preferences and routine and then make an energy-efficient schedule that fits. What’s even better is that you can regulate and watch your settings from just about anywhere with your phone, whether you’re sitting in bed or out and about. (You might even be able to receive a free smart thermostat depending on rebate programs from your utility supplier in Cottonwood.)

In many instances, installing a smart home thermostat with the assistance of Connolly Electric & Mechanical is a straightforward process if you have a new residence. But what if your house is older or doesn’t have the proper wiring? Can you still add a smart thermostat without C wire? We’ll help you figure out the process so you can pick the right thermostat and get energy savings for a long time.

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

The majority of programmable thermostats need batteries. When you’re upgrading to a smart thermostat, you’ll learn that many require a C wire, or common wire, for power. Without this wire, your new thermostat could cause your heating and cooling system to malfunction.

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

  1. Switch off 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’s needed for a smart thermostat. You might be thinking 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 almost there. Ensure the C wire isn’t tucked within the wall. If you can’t find one, we may be able to add one for you or you may be able to run your new thermostat without one.
  5. If you have two thick wires, you may be able to run a smart thermostat with an adaptor just for high-voltage systems. Or you may be able to operate a battery-powered smart thermostat, like the Lux Geo Wi-Fi Thermostat, if your wiring won’t work and you don’t want to put in new wiring.

Do Nest or ecobee Need a C Wire?

Two of the most popular brands are the Nest smart thermostat and ecobee smart thermostat. If you have two to four wires, these thermostats could be an option for your needs.

Nest says its thermostats are created to consume very little power and can often share it with your home comfort system. However, you may need to have a pro like Connolly Electric & Mechanical install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re running into power problems or a battery that’s always drained.

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

Rely on Connolly Electric & Mechanical for Your Smart Thermostat Installation Needs

At Connolly Electric & Mechanical, we’re always on the lookout for approaches to keep you cozier while keeping utility bills low. If you want to know more about switching to a smart thermostat without a C wire, give us a call at 928-639-4251. We can help you choose the right model for your home and even add new wiring if required.