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 decrease utility costs, upgrading to a smart thermostat is a wise idea. These devices pick up on the temperatures you like and routine and then make an energy-efficient schedule that fits. What’s even better is that you can regulate and keep an eye on your settings from just about anywhere with your phone, whether you’re sitting in bed or on the go. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility company in Stuart.)

Most of the time, installing a smart home thermostat with the support of Breathe Healthier Air is a straightforward job if you have a newer house. But what if your house is older or doesn’t have the proper wiring? Can you still install a smart thermostat without C wire? We’ll help you navigate the process so you can pick the correct thermostat and get energy savings for years to come.

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

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

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

  1. Cut power to the thermostat at the breaker.
  2. Pull off 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 wondering what color is the C wire on a thermostat—and the answer to that is usually blue.
  4. If there are three or four thin multicolored wires, you’re close. Check the C wire isn’t hidden 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 operate 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 is incompatible 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 could be a match for your needs.

Nest says its thermostats are made to require very little power and can often share it with your heating and cooling system. However, you may need to have a professional like Breathe Healthier Air install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re having power problems or a battery that’s constantly 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 covered if you don’t have a thermostat C wire.

Depend on Breathe Healthier Air for Your Smart Thermostat Installation Needs

At Breathe Healthier Air, we’re always looking for approaches to keep you more comfortable while keeping utility costs reasonable. If you want to know more about switching to a smart thermostat without a C wire, contact us at 772-353-4633. We can help you select the right model for your house and even add new wiring if needed.