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 energy expenses, getting a smart thermostat is a smart decision. These devices adjust to the temperatures you like and routine and then make an energy-efficient schedule to match. What’s even better is that you can change and keep an eye on your settings from just about anywhere with your phone, whether you’re lying in bed or out and about. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility supplier in Katy.)

Most of the time, adding a smart home thermostat with the support of Goode Bros AC & Heating is an uncomplicated process if you have a newer house. But what if your house is older or doesn’t have the correct wiring? Can you still install a smart thermostat without C wire? We’ll help you navigate the process so you can pick the proper thermostat and enjoy energy savings for many years.

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

Most programmable thermostats need batteries. When you’re making the move to a smart thermostat, you’ll learn that many have to have a C wire, or common wire, for power. If you don’t use this wire, your new thermostat could cause your heating and cooling system to malfunction.

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 needed for a smart thermostat. You might be pondering what color is the C wire on a thermostat—and the answer to that is typically blue.
  4. If there are three or four thin multicolored wires, you’re almost there. Ensure the C wire isn’t rolled up in 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 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 won’t work 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 a match for you.

Nest says its thermostats are made to require minimal power and can frequently share it with your heating and cooling system. However, you may need to have a pro like Goode Bros AC & Heating add 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 works with 24-volt systems (ones with three to six thermostat wires) and includes a C wire adaptor. So, you’re good if you don’t have a thermostat C wire.

Depend on Goode Bros AC & Heating for Your Smart Thermostat Installation Needs

At Goode Bros AC & Heating, we’re always looking for ways to keep you comfier while keeping utility bills inexpensive. If you want to know more about installing a smart thermostat without a C wire, reach us at (833)-466-3322. We can help you pick the right model for your residence and even add new wiring if needed.