The devices most commonly called “smart thermostats”, such as thermostats from Nest, Ecobee, Honeywell, etc., are only compatible with “low voltage” 24v HVAC systems. You should be certain that your HVAC is compatible before you try to hook up a smart thermostat.

How do you hook up a smart thermostat to a 2 wire system?

The procedure to install the Nest thermostat with 2 wires is the same for both thermostats.

  1. Turn off the power to your HVAC system.
  2. Remove the existing thermostat and mark the wires.
  3. Install the Nest Baseplate.
  4. If you have a heat only system you should connect your thermostat wires to the W terminal and Rh terminals.

What if my thermostat has only two wires?





If your heating system has only two wires, the job of the thermostat is simple. All it has to do is turn the heat or the cooling on and off. There’s no auxiliary fan to worry about and no heat pump.

Can I install a WIFI thermostat with only 2 wires?

The Nest Thermostat is not only the best 2 wire wifi thermostat but it is one of the best wifi thermostats you can get for your home. The Nest Generation 3 thermostat can be used with heating only and cooling only systems and requires only wires.

How many wires does a smart thermostat need?

4 Wire Thermostat Wiring (Heat Pumps, HVAC)



Smart thermostats like Nest and Ecobee thermostats require 4 wire thermostat wiring to function properly. In addition to heating (2 wire thermostats) and C or fan (3 wire thermostats), 4 wire thermostats include the cooling wire, usually in blue or yellow color.

How do I install a smart thermostat without C wire?

Quote from the video:
Quote from Youtube video: We only have four wires that are used you have the are wire the W wire the G wire and the wire most Wi-Fi thermostats.

How do you bypass a 2 wire thermostat?





Quote from the video:
Quote from Youtube video: Ones your jump ring stick this jumper in there and tighten those screws back up and flip the furnace which Bagon. Well guys and that is how you bypass your thermostat.

What if there is no C wire for thermostat?

You most likely have a line voltage system and none of the popular smart thermostats on the market are available to you as-is. (There is some hope with an adapter, but don’t get too excited yet.) This wiring indicates a line voltage system, and you’ll need an adapter or a smart thermostat designed for line voltage.

How do I install an Ecobee thermostat with 2 wires?

Quote from the video:
Quote from Youtube video: So it's just kind of a bypass it takes two wires in. And it goes from the two hours into one wire. And then that one wire goes into the fast app by your that that plugs in by your thermostat.

Is RC and C wire the same?

The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.

Can I use G wire for C wire?



Option #3: Use a G-Wire as a C-Wire



If there is no hidden C-wire, you can use a G-wire instead. However, you will not be able to use your fan independently when the heating or cooling isn’t running. Also, many HVAC systems are incompatible with this solution, including: HVAC systems using electric heat.

Can you run a Nest thermostat without a common wire?

You can install a Nest Thermostat without a C-wire by using a C-wire adapter, that mimics a traditional C-Wire without you having to wire it. If you are not a handyman, it saves a lot of money that you would otherwise have to spend on a professional installer too.

What color is the C wire?

Blue wires



Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.

How do you identify C wire?

Quote from the video:
Quote from Youtube video: Likely there is gonna be a fifth wire tucked into the wall I'm thinking that's going to be our C wire most likely because as you can see we have a green a yellow a white in a red.

What color wire goes where on a thermostat?

This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).

Do all smart thermostats require AC wire?

The good news is, some of the best smart thermostats do not require the power from the C wire to work. In fact, some of the best smart thermostats like the Google Nest Thermostat have no requirement for the C wire as they contain rechargeable batteries or other technology that removes the need for one.

What does C wire required mean?



What is a C-Wire? A common wire (C-Wire) provides Wi-Fi thermostats continuous power by connecting it to a heating and cooling system (e.g. furnace). C-Wires are required on most Honeywell Wi-Fi thermostats, with the exception of the Smart Round Thermostat (formerly known as the Lyric Round).

Does Nest e need C wire?

The Nest Thermostat E is designed to work even if your home doesn’t have a common (C) wire, but installing a new C wire may be required. If you have a dual fuel system, we strongly recommend professional installation.