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

June 09, 2021

When you’re wanting approaches to lower heating and cooling costs, installing a smart thermostat is a smart move. These devices pick up on the temperatures you like and routine and then make an energy-efficient schedule that matches. What’s even better is that you can regulate and watch your settings from almost anywhere with your phone, whether you’re relaxing in bed or out and about. (You might even be able to get a free smart thermostat depending on rebate programs from your utility company in Holdrege.)

Most of the time, hooking up a smart home thermostat with the support of Durable Service is a straightforward job if you have a new home. But what if your residence is older or doesn’t have the right wiring? Can you still add a smart thermostat without C wire? We’ll help you figure out the process so you can select the correct thermostat and enjoy energy savings for many years.

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

Many programmable thermostats need batteries. When you’re switching to a smart thermostat, you’ll discover that many have to have a C wire, or common wire, for power. Without this wire, your new thermostat might cause your heating and cooling system to malfunction.

You can ascertain 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 find the wiring.
  3. If there are five or six multicolored wires, you have what you need 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 nearly there. Check the C wire isn’t hidden inside the wall. If you can’t find one, we may be able to put in 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 use 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 won’t work 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 an option for you.

Nest says its thermostats are made to require minimal power and can often share it with your HVAC system. However, you may need to have a specialist like Durable Service add a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re running into power problems or a battery that’s frequently drained.

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

Trust Durable Service for Your Smart Thermostat Installation Needs

At Durable Service , we’re always on the lookout for approaches to keep you comfier while keeping heating and cooling bills reasonable. If you have questions about switching to a smart thermostat without a C wire, give us a call at 308-995-8177. We can help you choose the right model for your residence and even put in new wiring if necessary.