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 reduce energy expenses, getting a smart thermostat is a wise decision. These devices adjust to your temperature preferences and routine and then develop an energy-efficient schedule to match. What’s even better is that you can regulate and monitor your settings from just about anywhere with your phone, whether you’re sitting 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 Troy.)

In most instances, adding a smart home thermostat with the support of Edington Heating & Cooling Inc is a straightforward process if you have a more modern home. But what if your residence is older or doesn’t have the right wiring? Can you still add a smart thermostat without C wire? We’ll help you figure out the process so you can choose the proper thermostat and receive energy savings for many years.

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

Many programmable thermostats run on batteries. When you’re switching to a smart thermostat, you’ll find 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 malfunctions.

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

  1. Switch 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 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 rolled up in the wall. If you can’t find one, we may be able to add 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 designed 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 is incompatible and you don’t want to install new wiring.

Do Nest or ecobee Need a C Wire?

Two of the most popular 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 needs.

Nest says its thermostats are created to need minimal power and can typically share it with your heating and cooling system. However, you may need to have a professional like Edington Heating & Cooling Inc install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re running into power problems or a battery that’s constantly drained.

ecobee is compatible with 24-volt systems (ones with three to six thermostat wires) and has a C wire adaptor. So, you’re taken care of if you don’t have a thermostat C wire.

Rely on Edington Heating & Cooling Inc for Your Smart Thermostat Installation Needs

At Edington Heating & Cooling Inc, we’re always looking for approaches to keep you more comfortable while keeping energy bills low. If you want to know more about installing a smart thermostat without a C wire, give us a call at 937-558-9478. We can help you choose the right model for your home and even add new wiring if required.