Mathew's Air Comfort Solutions is now Mathew's CCAC!
(361) 235-3905 Request Service

What Homeowners Should Know About C-Wire

June 11, 2019 | Blog

What Homeowners Should Know About C-Wire	Does your HVAC system include a c-wire?  If you’re planning on upgrading to a newer, smarter thermostat, it’s a good thing to know.

While older thermostats typically have minimal power requirements—batteries handle most of it—new smart thermostats require a continuous source of 24 volt electricity from the system. It’s necessary to power the kind of convenience and efficiency advantages provided by these new, improved units such as wi-fi connectivity and large, bright multifunctional displays. To access this voltage, a c-wire (short for “common wire”) is necessary.

Checking For The Wire

Some homes come pre-wired with the HVAC common wire. If yours isn’t, installation of the wire will be required in order to accommodate the new thermostat. Here’s one good way to tell:

    • Remove the existing thermostat from it’s wall-mounted bracket. Usually, you’ll be able to see the wires that extend from inside the wall and are connected to terminals on the thermostat wall bracket.
    • Count the wires connected to the terminals.  If you count four, you probably lack the necessary c-wire and you’ll need to have one installed to power the new thermostat. If you count five wires, that usually means the common wire is already installed so you’re probably good to go with the new thermostat.  (In some cases, that extra fifth wire may not be connected to a terminal but just hanging loose or folded up. That simply means your existing thermostat didn’t require a c-wire.)
    • Note that wiring color isn’t a reliable way to determine if the common wire is present. There’s no dependably standard color for that wire.

What If You Need One?

If the common wire isn’t installed, a qualified HVAC contractor can do the job quickly. In most cases the wire will extend from the electronic control board in the furnace or AC to the thermostat in order to complete the continuous 24-volt circuit.

For more information about upgrading to a new thermostat and installing a c-wire if it’s necessary, contact the HVAC pros at CCAC.

Constantly Concerned About You!

noun_team_2578407
Professional Team
Our ac technicians are highly trained, professional and committed to getting the job done right the first time.
noun_assurance_426752
Reliable Service
You can count on our expert ac technicians to provide high-quality air conditioning services with quality products and transparent pricing.
noun_Handshake_2064250
Customer Service
You deserve excellent customer service. That's why we strive to be courteous and professional through the entire service process.

What Our Customers Are Saying

Pleasure to Work With

Mathews CCAC conducted the semi-annual inspection of the A/C, heating system for the fall check-up, Technician was on time, courteous and went quickly about the inspection and observed all COVID-19 protocols for his and our safety a pleasure to work with this company

Steven L.

Great Company

Great company. Contacted my current AC company to check on my warranty before charging me anything. Saved me a bunch of money and headache if dealing with anything. Would definitely recommend them and use them again.

Ryan W.

Very Satisfied

I’ve had a system purchased and installed by them for several years with the maintenance contract the whole time. I’ve been very satisfied with the service. You can’t go wrong selecting them for your business.

Joseph S.