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

June 09, 2021

When you’re looking for ways to decrease utility costs, upgrading to a smart thermostat is a wise idea. These devices adjust to your temperature preferences and routine and then create an energy-efficient schedule that matches. What’s even better is that you can change and monitor your settings from nearly anywhere with your phone, whether you’re lying in bed or out and about. (You might even be able to get a free smart thermostat depending on rebate programs from your utility company in Brookfield.)

In many instances, hooking up a smart home thermostat with the support of Central Air LLC is a simple job if you have a more modern home. But what if your house is older or doesn’t have the right wiring? Can you still add a smart thermostat without C wire? We’ll help you demystify the process so you can pick the right thermostat and get energy savings for years to come.

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

Most programmable thermostats run on batteries. When you’re making the move to a smart thermostat, you’ll learn that many require a C wire, or common wire, for power. If you don’t have this wire, your new thermostat could 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 required for a smart thermostat. You might be pondering 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 nearly there. Ensure the C wire isn’t tucked within the wall. If you can’t find one, we may be able to put in 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 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 put in 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 may be an option for you.

Nest says its thermostats are created to consume minimal power and can typically share it with your heating and cooling system. However, you may need to have a professional like Central Air LLC 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 has a C wire adaptor. So, you’re covered if you don’t have a thermostat C wire.

Rely on Central Air LLC for Your Smart Thermostat Installation Needs

At Central Air LLC, we’re always looking for methods to keep you more comfortable while keeping heating and cooling expenses inexpensive. If you want to learn more about upgrading to a smart thermostat without a C wire, contact us at 203-357-5913. We can help you select the right model for your house and even install new wiring if needed.