Buy Thermostat Wire [BEST]

During initial setup, the app will often tell you if you should connect a C wire to your thermostat. If your old thermostat had a C wire connected, the app will typically tell you to connect a C wire to your Nest thermostat.

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Important: Some systems, including heating-only, cooling-only, zone-controlled, and heat pump systems, require a C wire or a compatible power accessory, like the Nest Power Connector. The app will tell you if you need this.

A trained professional will be able to quickly tell what kind of system you have and identify the wires. They can also install and set up your Nest thermostat for you, and answer any questions you have. You can contact a local HVAC professional in your area to service your system.

In some heat pump systems, the W2 wire may control a separate furnace to help heat your home. These types of systems are called dual fuel systems because the heat pump and the furnace use different heat sources.

Wires labeled S or S1 can be indicator lights or sensor wires. The Nest thermostat uses its LCD display instead of an indicator light and gets sensor information, like outdoor weather conditions, over Wi-Fi.

Proprietary systems usually only work with thermostats made by the same manufacturer. But some proprietary systems may also have the option to use standard heating system wires. Contact a local HVAC professional and have them check if your proprietary system can be rewired to be Nest compatible.

Wiring a thermostat is basically connecting the correct-colored wires to the correct terminal. Understanding what each wire is for is critical to complete the procedure successfully. If you are unsure of any of the thermostat wiring, it is safer to contact a qualified professional.

If you have two wires, you almost certainly have a digital thermostat that solely provides heat (i.e. without air conditioning). Typically, the two wires are red and white (see above for information on where they are connected).

This is a popular configuration for a battery-powered thermostat or a digital thermostat that solely regulates heat. The standard configuration consists of 24-volt hot (red), 24-volt common (blue), heat (white), and a fan (green).

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).

The Thermostat Wire Adapter adds the function of a Common wire to your existing system with minimal effort and can get you up and running with the iDevices Thermostat in no time! The Thermostat Wire Adapter can also be used to add another wire if additional wiring cannot be run.

No matter if your thermostats are from third-party brands like Honeywell, Nest, Sensi, White Rodgers or Ecobee, or the same brands (Trane, Carrier, Goodman, etc.) as your HVAC systems, this guide will help familiarize you with the wiring process.

Success starts with knowing what type of thermostat wiring you have or need. Your options include 24V, 110/240V and millivolt thermostat. This guide addresses 24-volt systems, the majority of HVAC systems.

What uses 4 wire thermostat wiring? The most common 4 wire thermostat wiring is needed for heat pump systems that include a condensing unit outside and an air handler indoors. Unique to this system are the need for a fan wire and a wire to power AC cooling.

What uses 6 wire thermostat wiring? Heat pump systems with a C-wire and advanced heating and AC require 6 or more wires. For example, a two stage heat pump, one with Aux heat and/or one that has a reversing valve that needs power all require 6 wire thermostat wiring or more (7 and 8 wiring follow).

6). If it is a single stage heat pump but has Aux heat strips in the air handler, attach an unused wire, such as the Light Blue wire, to the X/Aux terminal for Auxiliary heat.

What uses 7 wire thermostat wiring? Many types of systems can. A heat pump with 2 stages of heating and cooling, a system with Aux heating or one that has a reversing valve that needs to be energized.

Many thermostats function without a C wire by periodically pulling power from one of the other wires, usually the red wire. However, if your thermostat information says a C wire is required, then this information is for you. The wire is needed for most brands and models including ecobee and Honeywell Lyric.

The important first step is to get the proper replacement wire type. It comes in bundles of 2, 3, 5, 6 and 8 wires. As you shop for it, these will be labeled 18/2, 18/3, 18/5, and so forth. Most systems today require a minimum of 5 wires when both heating and air conditioning equipment is included in the system.

Yes, this is excellent. Illustrations are great.My problem is a 2 stage compressor that has been ADDED to my Trane Furnace/AC unit that does NOT have a Y2 terminal. I see a RELAY has been added years ago, and the C terminal is used to run the wire to the Y2 of my existing thermostat. I want to install a Honeywell Wifi Thermostat, so still trying to figure out the wiring.

I have a situation where I tried installing a NEST Learning thermostat but it went dead after about 3 days. I have a 5 wires coming from the air handler on my system to the thermostat. Two red wires, a green, yellow and white. I had connected the red wires to the R and Rh terminals on the NEST. After it went dead I noticed that the red wire which comes from my boiler is connected to the C terminal on the air handler. Does this suggest that this red wire should be connected to the C terminal on the NEST thermostat?

Smart thermostats are also good for the planet: According to Energy Star, if every US household installed a smart thermostat, the energy savings would be equivalent to 1.2 million fewer vehicles on the road. Because of those potential savings, energy companies frequently offer rebates and incentives to replace a traditional thermostat with a smart one.

For example, you might configure your thermostat to lower the temperature when you leave the house and lock your front door. And it can automatically start warming the house when your garage door opens as you arrive home. These smart-home ecosystems are continually growing, so the interactions your thermostat is capable of are expanding as well (though sometimes only with the purchase of additional hardware).

Since this guide has been produced by two different reviewers, some smart thermostats mentioned throughout have been tested in different locations. For this most recent update, all of our thermostat picks except the Mysa were tested in a freestanding, single-zone home with a one-zone electric HVAC system, operating a heat pump (not a furnace).

These systems work well together to balance comfort and energy use, and in our testing the thermostat did a very good job of maintaining a comfortable temperature, while not using excessive energy when we were home.

An HVAC monitoring feature detects and notifies you of any problem with your system, such as a furnace shutdown or extended heating or cooling times. We had some experience with this feature in our testing of the more basic Nest Thermostat (see Other good smart thermostats).

Another essential smart feature of the Nest is its Eco Mode. This uses a combination of presence sensing and geofencing to determine when the house is empty and then tells the thermostat to keep temperatures within an energy-saving range. When it senses you are home or coming home, based on your habits and the location of your smartphone, it returns to its normal schedule.

The big caveat is that to make all the heating units in your system smart, you will need to replace every thermostat; this gets expensive quickly (though over time that up-front cost could be offset by energy-bill savings, since electric baseboard heating is so much less energy-efficient than other systems).

None of these companies offer discounts or incentives for upgrading from an older model. However, both Ecobee and Nest are widely available at discounted prices from utility companies through partner programs. And though all of the companies encourage owners to recycle devices when they eventually die, only Nest will provide a free shipping label and box to send in any thermostat for reclamation and data destruction; learn more about that here.

Although we strongly recommend our picks for most people, there are some scenarios in which they might be more than you need or not the right fit for your setup. Here are a few other smart thermostats that are worth considering.

Technically speaking, power flows from the R (red) wire, but not continuously (not on its own, anyway). To make it continuous requires a common wire to complete the circuit. When the circuit is complete, 24V energy will flow continuously.

This is exactly what I was looking for. I keep reading that the C-wire provides power for the thermostat but my electrical background knows common as ground (I know, big discussion of ground vs common). This explanation validates why my C-wire is connected to the grounded side of the 24 volt transformer. Thanks for the explanation.

I need the C wire for a thermostat that communicates with a wireless router. My old oil furnace and thermostat only have two wires between them, R and W. Since there is no existing transformer, I will need to rig one up (probably in a j box near the thermostat, spliced off a nearby outlet or something) So one of the 24v wires will go to the C terminal on the thermostat, but then the other to which terminal? R? Thx.

Due to old heater panel, I could not find the C wire to hook up. So, hooked up external transformer and connected to C and Rc. Removed jumper between Rc and Rh as suggested by Bill Lee below. Heater works. A/c does not work. 041b061a72