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

June 09, 2021

When you’re seeking methods to lower utility bills, getting a smart thermostat is an intelligent decision. 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 change and watch your settings from just about anywhere with your phone, whether you’re sitting in bed or away from home. (You might even be eligible for a free smart thermostat depending on rebate programs from your utility supplier in Jefferson City.)

In many instances, adding a smart home thermostat with the help of Stieferman Heating Company Inc is a simple job if you have a more modern house. But what if your residence is older or doesn’t have the right wiring? Can you still have a smart thermostat without C wire? We’ll help you figure out the process so you can choose the ideal 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 upgrading 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 might cause your heating and cooling system to have malfunctions.

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

  1. Turn off power to the thermostat at the breaker.
  2. Remove 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 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 almost there. Make sure the C wire isn’t hidden within the wall. If you can’t find one, we may be able to install 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 just 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 isn’t right 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 might be an option for your home.

Nest says its thermostats are made to consume very little power and can often share it with your HVAC system. However, you may need to have a professional like Stieferman Heating Company Inc 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 always 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 taken care of if you don’t have a thermostat C wire.

Depend on Stieferman Heating Company Inc for Your Smart Thermostat Installation Needs

At Stieferman Heating Company Inc, we’re always looking for approaches to keep you comfier while keeping utility costs inexpensive. If you have questions about switching to a smart thermostat without a C wire, give us a call at 573-203-3908. We can help you choose the right model for your residence and even add new wiring if needed.