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

June 09, 2021

When you’re looking for methods to decrease utility costs, installing a smart thermostat is a wise move. These devices learn your favorite temperatures and routine and then create an energy-efficient schedule that fits. What’s even better is that you can change and monitor your settings from just about anywhere with your phone, whether you’re relaxing in bed or away from home. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility provider in Racine.)

In many instances, adding a smart home thermostat with the support of Keystone Heating & Air Conditioning Co., Inc is a straightforward task if you have a new residence. But what if your house is older or doesn’t have the proper wiring? Can you still have a smart thermostat without C wire? We’ll help you demystify the process so you can pick the recommended thermostat and enjoy energy savings for a long time.

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

Most programmable thermostats run on 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 could cause your heating and cooling system to have glitches.

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

  1. Turn off power to the thermostat at the breaker.
  2. Take off 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 nearly there. Make sure the C wire isn’t rolled up in 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 run 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 won’t work 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 fit for your needs.

Nest says its thermostats are created to consume minimal power and can typically share it with your heating and cooling system. However, you may need to have a specialist like Keystone Heating & Air Conditioning Co., Inc install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re running into power problems or a battery that’s always 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 Keystone Heating & Air Conditioning Co., Inc for Your Smart Thermostat Installation Needs

At Keystone Heating & Air Conditioning Co., Inc, we’re always looking for approaches to keep you cozier while keeping energy costs low. If you want to learn more about installing a smart thermostat without a C wire, contact us at 262-358-9468. We can help you pick the right model for your residence and even install new wiring if required.