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

June 09, 2021

When you’re wanting approaches to lower energy bills, getting a smart thermostat is a smart move. These devices adjust to your favorite temperatures and routine and then make an energy-efficient schedule that fits. 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 on the go. (You might even be able to receive a free smart thermostat depending on rebate programs from your utility company in Front Royal.)

Most of the time, adding a smart home thermostat with the help of Dave's Diversified Services is a straightforward process if you have a newer home. But what if your home is older or doesn’t have the proper wiring? Can you still have a smart thermostat without C wire? We’ll help you figure out the process so you can select the proper thermostat and enjoy energy savings for a long time.

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 find that many have to have a C wire, or common wire, for power. Without this wire, your new thermostat may cause your heating and cooling system to have malfunctions.

You can ascertain 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 thinking 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 close. Check the C wire isn’t tucked inside the wall. If you can’t find one, we may be able to install one for you or you may be able to operate 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 replace it.

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 might be an option for your home.

Nest says its thermostats are created to run on very little power and can frequently share it with your home comfort system. However, you may need to have a specialist like Dave's Diversified Services install 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 comes with a C wire adaptor. So, you’re taken care of if you don’t have a thermostat C wire.

Trust Dave's Diversified Services for Your Smart Thermostat Installation Needs

At Dave's Diversified Services, we’re always on the lookout for approaches to keep you more comfortable while keeping heating and cooling expenses low. If you want to learn more about upgrading to a smart thermostat without a C wire, reach us at 540-369-3971. We can help you pick the right model for your house and even add new wiring if needed.