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

June 09, 2021

When you’re wanting methods to reduce heating and cooling bills, installing a smart thermostat is an intelligent decision. These devices pick up on your temperature preferences and routine and then create an energy-efficient schedule that matches. 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 lying in bed or away from home. (You might even be able to get a free smart thermostat depending on rebate programs from your utility supplier in Plainfield.)

In many instances, hooking up a smart home thermostat with the assistance of PWA Heating & Cooling Inc is an uncomplicated job if you have a newer home. But what if your house is older or doesn’t have the proper wiring? Can you still add a smart thermostat without C wire? We’ll help you demystify the process so you can pick the proper thermostat and enjoy energy savings for years to come.

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

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

You can find out 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 find the wiring.
  3. If there are five or six multicolored wires, you have what’s needed for a smart thermostat. You might be wondering what color is the C wire on a thermostat—and the answer to that is usually blue.
  4. If there are three or four thin multicolored wires, you’re nearly there. Check 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 operate your new thermostat without one.
  5. If you have two thick wires, you may be able to run a smart thermostat with an adaptor specifically 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 put in 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 may be a fit for your home.

Nest says its thermostats are created to run on minimal power and can frequently share it with your heating and cooling system. However, you may need to have a specialist like PWA Heating & Cooling 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 is compatible 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 PWA Heating & Cooling Inc for Your Smart Thermostat Installation Needs

At PWA Heating & Cooling Inc, we’re always seeking ways to keep you cozier while keeping heating and cooling costs reasonable. If you want to learn more about upgrading to a smart thermostat without a C wire, reach us at 815-410-1231. We can help you select the right model for your house and even put in new wiring if required.