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

June 09, 2021

When you’re looking for methods to reduce utility expenses, getting a smart thermostat is an intelligent decision. These devices adjust to your temperature preferences and routine and then create an energy-efficient schedule that fits. What’s even better is that you can change and keep an eye on 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 get a free smart thermostat depending on rebate programs from your utility supplier in Brandon.)

In most instances, installing a smart home thermostat with the support of Brandon Heating and Plumbing is an uncomplicated job if you have a more modern house. But what if your home is older or doesn’t have the correct wiring? Can you still have a smart thermostat without C wire? We’ll help you figure out the process so you can select the ideal thermostat and get energy savings for years to come.

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

Most programmable thermostats run on batteries. When you’re switching to a smart thermostat, you’ll find that many need 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 ascertain if you have a C wire by doing the following:

  1. Cut 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’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. Make sure the C wire isn’t rolled up inside 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 run a smart thermostat with an adaptor designed for high-voltage systems. Or you may be able to install 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 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 home.

Nest says its thermostats are designed to require minimal power and can typically share it with your heating and cooling system. However, you may need to have a pro like Brandon Heating and Plumbing 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 is compatible 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 Brandon Heating and Plumbing for Your Smart Thermostat Installation Needs

At Brandon Heating and Plumbing, we’re always on the lookout for methods to keep you comfier while keeping utility bills low. If you want to learn more about switching to a smart thermostat without a C wire, contact us at 204-728-0180. We can help you choose the right model for your residence and even add new wiring if required.