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

June 09, 2021

When you’re seeking approaches to reduce heating and cooling bills, getting a smart thermostat is an intelligent idea. These devices adjust to your favorite temperatures and routine and then develop an energy-efficient schedule that fits. What’s even better is that you can regulate and watch your settings from just about anywhere with your phone, whether you’re lying in bed or on the go. (You might even be able to get a free smart thermostat depending on rebate programs from your utility supplier in Anaheim.)

In many instances, installing a smart home thermostat with the assistance of Eco Fresh HVAC Inc. is a straightforward task if you have a more modern residence. But what if your house is older or doesn’t have the right wiring? Can you still add a smart thermostat without C wire? We’ll help you navigate the process so you can choose the correct thermostat and enjoy energy savings for many years.

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

Most programmable thermostats run on batteries. When you’re making the move to a smart thermostat, you’ll find that many have to have a C wire, or common wire, for power. If you don’t have this wire, your new thermostat may cause your heating and cooling system to malfunction.

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

  1. Turn 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 required for a smart thermostat. You might be pondering what color is the C wire on a thermostat—and the answer to that is typically blue.
  4. If there are three or four thin multicolored wires, you’re close. Ensure the C wire isn’t tucked in the wall. If you can’t find one, we may be able to add 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 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 isn’t right and you don’t want to replace it.

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 work for your home.

Nest says its thermostats are designed to require minimal power and can often share it with your heating and cooling system. However, you may need to have a professional like Eco Fresh HVAC Inc. add 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 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 Eco Fresh HVAC Inc. for Your Smart Thermostat Installation Needs

At Eco Fresh HVAC Inc., we’re always looking for approaches to keep you cozier while keeping heating and cooling costs reasonable. If you want to know more about upgrading to a smart thermostat without a C wire, reach us at 714-855-1717. We can help you pick the right model for your home and even add new wiring if necessary.