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

June 09, 2021

When you’re seeking methods to reduce heating and cooling expenses, installing a smart thermostat is a smart move. These devices adjust to your favorite temperatures and routine and then develop an energy-efficient schedule to match. What’s even better is that you can regulate and watch your settings from just about anywhere with your phone, whether you’re lying in bed or on the go. (You might even be able to receive a free smart thermostat depending on rebate programs from your utility supplier in Keokuk.)

In many instances, adding a smart home thermostat with the help of WM J Kraus & Son is a simple task if you have a newer house. But what if your home 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 select the recommended thermostat and get energy savings for many years.

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 find that many have to have a C wire, or common wire, for power. If you don’t have this wire, your new thermostat might cause your heating and cooling system to have malfunctions.

You can ascertain 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 find the wiring.
  3. If there are five or six multicolored wires, you have what’s required 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 almost there. Ensure the C wire isn’t tucked 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 designed 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 isn’t right and you don’t want to install new wiring.

Do Nest or ecobee Need a C Wire?

Two of the top 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 require not a lot of power and can frequently share it with your home comfort system. However, you may need to have a pro like WM J Kraus & Son put in 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 connects with 24-volt systems (ones with three to six thermostat wires) and includes a C wire adaptor. So, you’re good if you don’t have a thermostat C wire.

Rely on WM J Kraus & Son for Your Smart Thermostat Installation Needs

At WM J Kraus & Son, we’re always seeking ways to keep you more comfortable while keeping heating and cooling expenses inexpensive. If you want to learn more about installing a smart thermostat without a C wire, reach us at 319-229-2318. We can help you pick the right model for your home and even install new wiring if necessary.