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

June 09, 2021

When you’re wanting methods to decrease heating and cooling expenses, upgrading to a smart thermostat is an intelligent move. These devices pick up on your favorite temperatures and routine and then develop an energy-efficient schedule to match. What’s even better is that you can adjust and keep an eye on your settings from almost anywhere with your phone, whether you’re sitting in bed or out and about. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility company in Haines City.)

In many instances, hooking up a smart home thermostat with the support of Air Commander's Heating & Air Conditioning Co. is a straightforward job if you have a more modern home. But what if your home is older or doesn’t have the correct wiring? Can you still have a smart thermostat without C wire? We’ll help you figure out the process so you can choose the correct thermostat and receive energy savings for a long time.

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

Many programmable thermostats use 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 may cause your heating and cooling system to have glitches.

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

  1. Cut 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 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 nearly there. Check the C wire isn’t rolled up in 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 install a smart thermostat with an adaptor just for high-voltage systems. Or you may be able to use 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 may be an option for you.

Nest says its thermostats are designed to consume not a lot of power and can typically share it with your HVAC system. However, you may need to have a pro like Air Commander's Heating & Air Conditioning Co. add a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re experiencing power problems or a battery that’s always drained.

ecobee works 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.

Rely on Air Commander's Heating & Air Conditioning Co. for Your Smart Thermostat Installation Needs

At Air Commander's Heating & Air Conditioning Co., we’re always on the lookout for methods to keep you comfier while keeping energy expenses low. If you want to learn more about installing a smart thermostat without a C wire, give us a call at 863-216-2923. We can help you choose the right model for your residence and even put in new wiring if needed.