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

June 09, 2021

When you’re wanting methods to decrease energy costs, upgrading to a smart thermostat is a smart decision. These devices adjust to your favorite temperatures and routine and then make an energy-efficient schedule that matches. What’s even better is that you can change and keep an eye on your settings from nearly anywhere with your phone, whether you’re sitting in bed or away from home. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility supplier in Westerville.)

Most of the time, hooking up a smart home thermostat with the support of Uptown Heating & Cooling is a simple task if you have a more modern house. But what if your residence 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 many years.

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

The majority of programmable thermostats need batteries. When you’re making the move to a smart thermostat, you’ll discover that many require a C wire, or common wire, for power. Without this wire, your new thermostat might cause your heating and cooling system to have malfunctions.

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

  1. Turn off power to the thermostat at the breaker.
  2. Take off the thermostat and find 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 usually blue.
  4. If there are three or four thin multicolored wires, you’re nearly there. Check the C wire isn’t tucked in the wall. If you can’t find one, we may be able to add 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 install a smart thermostat with an adaptor designed 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 isn’t right and you don’t want to install new wiring.

Do Nest or ecobee Need a C Wire?

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

Nest says its thermostats are designed to require minimal power and can often share it with your heating and cooling system. However, you may need to have a pro like Uptown Heating & Cooling install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re having power problems or a battery that’s always drained.

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

Depend on Uptown Heating & Cooling for Your Smart Thermostat Installation Needs

At Uptown Heating & Cooling, we’re always looking for ways to keep you comfier while keeping heating and cooling bills inexpensive. If you want to know more about installing a smart thermostat without a C wire, contact us at 614-344-6949. We can help you select the right model for your home and even put in new wiring if required.