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

June 09, 2021

When you’re looking for ways to reduce energy bills, getting a smart thermostat is a smart decision. These devices learn your favorite temperatures and routine and then develop an energy-efficient schedule that fits. What’s even better is that you can change and monitor your settings from nearly anywhere with your phone, whether you’re lying in bed or out and about. (You might even be able to receive a free smart thermostat depending on rebate programs from your utility supplier in Safford.)

Most of the time, hooking up a smart home thermostat with the assistance of B&D Air Conditioning is a straightforward job if you have a newer home. But what if your home is older or doesn’t have the correct wiring? Can you still install a smart thermostat without C wire? We’ll help you figure out the process so you can choose the proper thermostat and get energy savings for a long time.

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

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

You can determine 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 find the wiring.
  3. If there are five or six multicolored wires, you have what you need 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 close. Make sure the C wire isn’t rolled up within the wall. If you can’t find one, we may be able to add one for you or you may be able to run 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 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 could be a match for your needs.

Nest says its thermostats are designed to run on not a lot of power and can typically share it with your HVAC system. However, you may need to have a specialist like B&D Air Conditioning install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re having power problems or a battery that’s frequently drained.

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

Trust B&D Air Conditioning for Your Smart Thermostat Installation Needs

At B&D Air Conditioning, we’re always on the lookout for ways to keep you more comfortable while keeping utility bills inexpensive. If you want to know more about installing a smart thermostat without a C wire, contact us at 928-432-6018. We can help you choose the right model for your house and even add new wiring if needed.