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

June 09, 2021

When you’re seeking approaches to lower utility expenses, getting a smart thermostat is a wise move. These devices adjust to your temperature preferences and routine and then create an energy-efficient schedule to match. What’s even better is that you can adjust and watch your settings from nearly anywhere with your phone, whether you’re lying in bed or away from home. (You might even be able to get a free smart thermostat depending on rebate programs from your utility company in Wyandotte.)

In most instances, hooking up a smart home thermostat with the assistance of Gee & Missler Heating & Air Conditioning is a simple process if you have a newer home. But what if your residence is older or doesn’t have the correct wiring? Can you still install a smart thermostat without C wire? We’ll help you figure out the process so you can pick the proper thermostat and receive energy savings for many years.

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

Many programmable thermostats run on batteries. When you’re upgrading to a smart thermostat, you’ll learn that many need 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. Switch off power to the thermostat at the breaker.
  2. Remove the thermostat and look at the wiring.
  3. If there are five or six multicolored wires, you have what’s required 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. 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 install a smart thermostat with an adaptor specifically 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 is incompatible and you don’t want to install 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 might be an option for your needs.

Nest says its thermostats are created to require not a lot of power and can often share it with your heating and cooling system. However, you may need to have a pro like Gee & Missler Heating & Air Conditioning add a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re having power problems or a battery that’s frequently drained.

ecobee works 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.

Rely on Gee & Missler Heating & Air Conditioning for Your Smart Thermostat Installation Needs

At Gee & Missler Heating & Air Conditioning, we’re always seeking methods to keep you cozier while keeping energy expenses reasonable. If you have questions about switching to a smart thermostat without a C wire, reach us at 734-363-8907. We can help you choose the right model for your home and even add new wiring if needed.