$50 Off a Service Call

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

June 09, 2021

When you’re seeking methods to reduce heating and cooling bills, installing a smart thermostat is a wise idea. These devices pick up on your temperature preferences and routine and then make an energy-efficient schedule to match. What’s even better is that you can regulate and watch your settings from almost anywhere with your phone, whether you’re lying in bed or out and about. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility provider in San Jose.)

In many instances, installing a smart home thermostat with the assistance of American HVAC Inc is a simple process if you have a more modern residence. But what if your residence is older or doesn’t have the right wiring? Can you still have a smart thermostat without C wire? We’ll help you figure out the process so you can choose the correct thermostat and enjoy energy savings for a long time.

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

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

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

  1. Switch 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 thinking 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. Ensure the C wire isn’t rolled up within 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 designed 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 replace it.

Do Nest or ecobee Need a C Wire?

Two of the top brands are the Nest smart thermostat and ecobee smart thermostat. If you have two to four wires, these thermostats might be a fit for you.

Nest says its thermostats are made to run on very little power and can typically share it with your home comfort system. However, you may need to have a pro like American HVAC Inc install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re experiencing power problems or a battery that’s frequently drained.

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

Rely on American HVAC Inc for Your Smart Thermostat Installation Needs

At American HVAC Inc, we’re always looking for approaches to keep you comfier while keeping utility bills reasonable. If you want to learn more about upgrading to a smart thermostat without a C wire, reach us at 408-215-1018. We can help you select the right model for your house and even put in new wiring if necessary.