24 Years Of Experienece
24 Years Of Experienece

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Smart Thermostat with Text

Smart thermostats in homes have begun to gain popularity in recent years, and it’s not hard to see why. The most recent statistics report that one in eight American houses have a programmable thermostat. And it’s projected that by 2020, nearly 40 million homes will be using a smart thermostat to help regulate heating and cooling.

But with the sudden rush to leverage modern technology to optimize and control your home’s heating and cooling, there’s one very important question you need to consider.

Should you have a professional install the system?

Depending on who you ask, the overwhelming answer seems to be a resounding “maybe.” To help clear up the confusion, we want to provide a concise guide to help you determine if you need to set up an appointment with an electrician.

Thankfully, there’s one question that will allow you to cut through the clutter and give you a clear direction:

Does Your Home Have a C-Wire?

Older thermostats only required a single wire to deliver power to your home’s heating and cooling system. They didn’t have bells and whistles like WiFi connectivity, so that was all you needed.

Modern thermostats require a second wire to complete the circuit and provide enough power to give all of the proper functionality. This second wire is called the C-wire, or common wire.

If you want to check if your home has a C-wire, all you need to do is carefully remove your thermostat and check the wiring labels.

Even if you don’t see the wire initially, it’s also worth checking your furnace’s access panel to see if a C-wire was indeed run. It’s possible that the wire is in the wall behind the thermostat and can still be accessed.

Yes, I Have a C-Wire

For homes that have this C-wire, there’s a good chance that you can install a smart device by yourself. As long as you follow the manufacturer’s instructions and take the necessary precautions, you can have your smart thermostat up and running in no time.

What if I Don’t Have a C-Wire?

If you don’t have a C-wire installed, then you should hire a professional to install a smart thermostat. It’s possible to find versions that don’t require a C-wire, but they’re known to malfunction frequently or stop working altogether.

Your best option is to have a C-wire properly installed and run to your new thermostat, which means it will require an electrician’s expertise. Even if you find a DIY article or video online, the risk to your health or home isn’t worth it when dealing electrical wiring.


It’s always a good idea to consult a professional to be sure you install your smart thermostat correctly. The potential to do something wrong could damage your home or lead to an electrical shock.

Castle Electric takes pride in our ability to install smart thermostats both quickly and safely. You’ll be saving energy and enjoying your connected home in no time!