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

June 09, 2021

When you’re seeking ways to decrease utility costs, upgrading to a smart thermostat is an intelligent move. These devices learn your favorite temperatures and routine and then create an energy-efficient schedule to match. What’s even better is that you can change and watch your settings from just about 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 Bend.)

In most instances, adding a smart home thermostat with the help of Tri County Climate Control LLC is a straightforward task if you have a newer home. But what if your home is older or doesn’t have the proper wiring? Can you still add a smart thermostat without C wire? We’ll help you figure out the process so you can select the ideal thermostat and get energy savings for years to come.

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

The majority of programmable thermostats use batteries. When you’re making the move to a smart thermostat, you’ll discover that many require 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 have glitches.

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. Pull 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 wondering 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. Check the C wire isn’t rolled up in 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 run a smart thermostat with an adaptor just 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 best-selling brands are the Nest smart thermostat and ecobee smart thermostat. If you have two to four wires, these thermostats might work for your home.

Nest says its thermostats are created to need minimal power and can often share it with your heating and cooling system. However, you may need to have a pro like Tri County Climate Control LLC install 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 is compatible with 24-volt systems (ones with three to six thermostat wires) and comes with a C wire adaptor. So, you’re good if you don’t have a thermostat C wire.

Depend on Tri County Climate Control LLC for Your Smart Thermostat Installation Needs

At Tri County Climate Control LLC, we’re always on the lookout for ways to keep you comfier while keeping energy expenses low. If you want to know more about installing a smart thermostat without a C wire, contact us at 541-238-2797. We can help you select the right model for your residence and even add new wiring if necessary.