I Want a Smart Thermostat but Don't Have a C Wire - What Are My Options?

June 09, 2021

When you’re wanting ways to reduce heating and cooling costs, installing a smart thermostat is a wise decision. These devices pick up on the temperatures you like and routine and then make an energy-efficient schedule that fits. What’s even better is that you can adjust and watch your settings from almost 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 Cedar Rapids.)

In many instances, hooking up a smart home thermostat with the assistance of Ilten's Incorporated is a simple process if you have a new house. But what if your residence 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 select the right thermostat and get energy savings for years to come.

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

Many programmable thermostats use batteries. When you’re making the move to a smart thermostat, you’ll find 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 find out if you have a C wire by doing the following:

  1. Switch 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’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 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 install 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 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 work for your needs.

Nest says its thermostats are created to need not a lot of power and can frequently share it with your home comfort system. However, you may need to have a specialist like Ilten's Incorporated put in a C wire with the Nest Thermostat E or Nest Learning Thermostat if you’re running into power problems or a battery that’s constantly drained.

ecobee connects 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.

Rely on Ilten's Incorporated for Your Smart Thermostat Installation Needs

At Ilten's Incorporated, we’re always on the lookout for methods to keep you comfier while keeping energy expenses low. If you have questions about upgrading to a smart thermostat without a C wire, give us a call at 319-208-3295. We can help you choose the right model for your house and even install new wiring if required.