A C-wire, or a common wire, runs from your low-voltage
In many recently-constructed homes, the HVAC c-wire is already installed. However, in homes that are only a few years old or older, the wire may need to be installed as part of the new smart thermostat installation.
While your thermostat may not technically need a C-wire to operate, it gets the power for its screen and Wi-Fi capabilities through “phantom power” or “power stealing.” Basically, this means your thermostat gets a kick of extra power whenever your HVAC system is running.
All thermostats use low voltage from the other connectors and typically use the batteries as a backup when there's no C wire.
The majority of modern heating/cooling/heat pump thermostats operate on low voltage (typically 24 volts AC) control circuits. The source of the 24 volt AC power is a control transformer installed as part of the heating/cooling equipment.
As mentioned above, most household electronics are powered through AC current, and the same can be said for businesses and offices. Some common applications for AC power include: Large appliances like refrigerators, air conditioners, and washing machines. High power and long-distance transmissions.
Not ALL smart thermostats require a C-wire but can work with one. Check the HVAC Compatibility section on our smart thermostat product pages for C-wire requirements. Some HVAC systems require a C-wire regardless of the thermostat.
A 2-wire thermostat is almost always for a system with heat but without air conditioning, controlled by a digital thermostat. The two wires are most often red for power and white for heat.
In today's electric market, most newer heating and cooling systems have C-wires, which guarantees compatibility for the installation of all smart thermostats. If you don't have a low-voltage heating system, you won't have a C-wire.
Most homeowners decide hiring a nearby electrician is worth the C-wire installation cost to ensure everything works right on the first try. Keep in mind that the typical cost to install a C-wire is $120 to $200.
Your thermostat reads the temperature of the room, then sends an on or off signal to the air conditioner. The AC itself isn't detecting the temperature in your home, so it has to rely on the thermostat.
The answer is yes; a smart thermostat can replace a regular one. However, the installation becomes more complex in certain situations. For example, newer homes have a C-wire (common wire) in them, while many older ones don't. Most smart thermostats require a C-wire.
If there isn't a C wire, you have 2 options: get a pro installer to run a new C wire from your system to your thermostat, which can be expensive, or you can install the Nest Power Connector, which is usually simpler and more affordable.
Wired vs. Wireless thermostat: Wired thermostats are directly connected to the heating system via cables. Wireless thermostat communicates with the heating system using radio frequencies.
The C, or common wire, provides smart thermostats with continual power. It's usually blue, but it may also be black, brown or purple. The O or orange wire connects to your heat pump (if applicable).
As you come and go, the thermostat adjusts the temperature to keep you comfortable when you're home without wasting energy when you're away. Energy savings: A smart thermostat can save you a modest amount of money on your electric bills. According to ENERGY STAR, the average savings are about 8 percent, or $50 a year.
Amazon Smart Thermostat – ENERGY STAR certified, DIY install, Works with Alexa – C-wire required.
You'll usually find a green wire, white wire, 24-volt R wire, and 24-volt common wire. 5-Wire Thermostats: A 5-wire thermostat is most typical for a home heating and AC system. This includes wires for power, heating, cooling, the fan, and a smart thermostat.
You can get both. The typcial electrically-powered refrigerator uses a compressor motor to pump refrigerant and you can use AC motors for home and residential use and you can get 12 V DC motors for small fridges for RVs, campers and small boats.
You may use an oscilloscope to determine whether a signal is AC or DC. If the output when the output wires are connected to the oscilloscope has a sinusoidal waveform, it is AC. An output of direct current (DC) is represented as a straight line.
A microwave oven generally consists of: a high-voltage DC power source, either: a large high voltage transformer with a voltage doubler (a high-voltage capacitor and a diode) an electronic power converter usually based around an inverter.