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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 ways to reduce heating and cooling bills, upgrading to a smart thermostat is an intelligent idea. These devices adjust to the temperatures you like and routine and then develop an energy-efficient schedule that fits. What’s even better is that you can change 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 company in Anchorage.)

In most instances, adding a smart home thermostat with the assistance of Discount Mechanical Heating & Plumbing Services is a straightforward task if you have a new house. But what if your house is older or doesn’t have the proper wiring? Can you still install a smart thermostat without C wire? We’ll help you demystify the process so you can select the ideal thermostat and enjoy energy savings for years to come.

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

The majority of programmable thermostats run on batteries. When you’re switching to a smart thermostat, you’ll learn that many have to have a C wire, or common wire, for power. If you don’t use this wire, your new thermostat may cause your heating and cooling system to have glitches.

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

  1. Switch off power to the thermostat at the breaker.
  2. Take off the thermostat and check the wiring.
  3. If there are five or six multicolored wires, you have what’s needed 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. 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 use your new thermostat without one.
  5. If you have two thick wires, you may be able to install 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 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 could work for your needs.

Nest says its thermostats are created to need not a lot of power and can typically share it with your heating and cooling system. However, you may need to have a pro like Discount Mechanical Heating & Plumbing Services install a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re experiencing power problems or a battery that’s always drained.

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

Depend on Discount Mechanical Heating & Plumbing Services for Your Smart Thermostat Installation Needs

At Discount Mechanical Heating & Plumbing Services, we’re always on the lookout for ways to keep you cozier while keeping utility bills reasonable. If you want to learn more about upgrading to a smart thermostat without a C wire, give us a call at 907-202-9798. We can help you pick the right model for your residence and even add new wiring if necessary.