What is a C-Wire?

A C-Wire is short for common wire. It is a wire that lives inside your thermostat and provides continuous power from your HVAC to the device. Although it does not directly control your heating or cooling, a smart thermostat needs constant connectivity to your Wifi in order to work properly, as well as for the digital screen to display.

Do I need a C-Wire?

Because smart thermostats require more power than their predecessors, making sure you have a C-Wire can save you headaches down the road. Many smart thermostats do require them to run, however there are some companies that claim their devices don’t need them. One way a company can get away with saying you don’t need a C-Wire is if the device “power steals”. This refers to the device stealing a small amount of power from the existing circuits to keep the battery in the device charged. The problem is that HVAC circuits are not designed for this, leaving the thermostat vulnerable to shutting down anyway, and your HVAC system inoperable.

C-Wire installation.

There are many how-to blogs, vlogs and even kits on installing a C-Wire on your own. The problem is that athough C-Wires are also called common wires they do not have a uniform color, its labeling can vary and often it is absent altogether. And if efficiency is the key with all of these smart devices being made for our homes, why not make sure you do it right the first time?

Now that’s smart!

Mister Sparky’s Smart home service can help you get your home ready for your smart equipment needs! Call Mister Sparky® of San Antonio today at (210) 899-2430!