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

June 09, 2021

When you’re looking for approaches to reduce energy expenses, getting a smart thermostat is an intelligent idea. These devices pick up on your favorite temperatures and routine and then create an energy-efficient schedule that matches. What’s even better is that you can adjust and watch your settings from almost anywhere with your phone, whether you’re relaxing 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 Bishop.)

In many instances, installing a smart home thermostat with the support of Bishop Heating & Air Conditioning is a straightforward task if you have a more modern home. But what if your home is older or doesn’t have the proper wiring? Can you still have 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 many years.

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

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

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 look at 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 typically blue.
  4. If there are three or four thin multicolored wires, you’re nearly there. Check the C wire isn’t tucked within the wall. If you can’t find one, we may be able to put in 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 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 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 might be an option for your needs.

Nest says its thermostats are created to consume minimal power and can often share it with your heating and cooling system. However, you may need to have a specialist like Bishop Heating & Air Conditioning add a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re experiencing power problems or a battery that’s constantly drained.

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

Depend on Bishop Heating & Air Conditioning for Your Smart Thermostat Installation Needs

At Bishop Heating & Air Conditioning, we’re always on the lookout for ways to keep you cozier while keeping energy bills low. If you have questions about installing a smart thermostat without a C wire, reach us at 760-784-9034. We can help you select the right model for your home and even put in new wiring if needed.