I Want a Smart Thermostat but Don't Have a C Wire - What Are My Options?

June 09, 2021

When you’re seeking methods to reduce energy bills, getting a smart thermostat is a smart decision. These devices adjust to the temperatures you like and routine and then create an energy-efficient schedule that matches. 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 on the go. (You might even be able to receive a free smart thermostat depending on rebate programs from your utility company in Thedford.)

Most of the time, installing a smart home thermostat with the assistance of Taylor's Heating & Air Conditioning is a simple task if you have a new residence. But what if your house is older or doesn’t have the right wiring? Can you still have a smart thermostat without C wire? We’ll help you demystify the process so you can select the right thermostat and enjoy energy savings for many years.

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

Many programmable thermostats use batteries. When you’re switching to a smart thermostat, you’ll discover that many need a C wire, or common wire, for power. Without this wire, your new thermostat could cause your heating and cooling system to have glitches.

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

  1. Turn off power to the thermostat at the breaker.
  2. Remove the thermostat and check the wiring.
  3. If there are five or six multicolored wires, you have what’s required for a smart thermostat. You might be pondering 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 almost there. Make sure the C wire isn’t tucked in the wall. If you can’t find one, we may be able to install 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 use a smart thermostat with an adaptor specifically for high-voltage systems. Or you may be able to operate a battery-powered smart thermostat, like the Lux Geo Wi-Fi Thermostat, if your wiring won’t work and you don’t want to put in 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 may work for your needs.

Nest says its thermostats are made to need minimal power and can typically share it with your HVAC system. However, you may need to have a professional like Taylor's Heating & Air Conditioning put in 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 has a C wire adaptor. So, you’re covered if you don’t have a thermostat C wire.

Depend on Taylor's Heating & Air Conditioning for Your Smart Thermostat Installation Needs

At Taylor's Heating & Air Conditioning, we’re always on the lookout for methods to keep you more comfortable while keeping energy expenses reasonable. If you have questions about installing a smart thermostat without a C wire, reach us at 519-296-4437. We can help you select the right model for your home and even add new wiring if necessary.