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

June 09, 2021

When you’re wanting methods to decrease energy bills, getting a smart thermostat is an intelligent idea. These devices pick up on the temperatures you like and routine and then create an energy-efficient schedule to match. What’s even better is that you can regulate and watch your settings from almost anywhere with your phone, whether you’re lying 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 Long Beach.)

Most of the time, installing a smart home thermostat with the assistance of YES R&M Inc. is an uncomplicated task if you have a newer home. But what if your house is older or doesn’t have the correct wiring? Can you still add a smart thermostat without C wire? We’ll help you navigate the process so you can select the correct thermostat and get energy savings for a long time.

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

Many programmable thermostats run on batteries. When you’re upgrading to a smart thermostat, you’ll discover 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 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 find 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 usually blue.
  4. If there are three or four thin multicolored wires, you’re close. Check the C wire isn’t rolled up 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 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 is incompatible 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 could be a fit for your home.

Nest says its thermostats are designed to need not a lot of power and can typically share it with your HVAC system. However, you may need to have a professional like YES R&M 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 constantly 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.

Trust YES R&M Inc. for Your Smart Thermostat Installation Needs

At YES R&M Inc., we’re always on the lookout for approaches to keep you more comfortable while keeping utility bills inexpensive. If you want to know more about switching to a smart thermostat without a C wire, give us a call at 562-286-6624. We can help you select the right model for your home and even put in new wiring if necessary.