How to Install the Nest Thermostat

A complete Nest installation guide

The Google Nest Learning Thermostat

Google Nest

If you don’t feel like a particularly handy DIY type of person, the idea of installing a Nest thermostat might seem overwhelming. Take heart, it’s not that challenging, and most of today’s smart, Wi-Fi-connected thermostats are meant to be installed by you, the homeowner. So, it's no surprise that Nest installation is easy enough that anyone can do it.

Before getting started with this Nest installation guide, we recommend you completely read the manufacturer's instructions and use proper safety precautions for wiring installations.

Getting Prepared for Nest Installation

First things first, make sure your system is compatible by answering a few questions about your HVAC system here. If your home’s compatible, and you have your Nest in hand, it’s time to go to work. Everything you'll need to install your new Nest thermostat should come in the box.

Google Nest Box Contents
Google Nest

It doesn’t matter if you’re installing the regular Nest or their also excellent budget-priced Nest E. The installation is nearly identical.

How to Remove the Old Thermostat

Turn off the breaker to you furnace or HVAC system before doing anything else, then follow these steps for removing your old thermostat.

  1. Remove the body of the old thermostat from it’s mounting plate.

  2. Once the thermostat is loose, snap a picture of the thermostat’s wiring for future reference. You’ll want to use this picture later, so this is an important step.

    Wiring Photo

    The Nest comes with wire labeling stickers—just put the right sticker on the appropriately labeled wire going into the mounting plate. Generally, if your current thermostat was installed properly, the wires should be color coordinated, but it’s best to make sure.

  3. Once you've documented the wiring, finish disconnecting the existing thermostat from the wall.

How to Install the Nest Thermostat Base

Once the old thermostat is gone, you can begin the process of installing your new Nest thermostat. It starts with installing a base on which the thermostat will mount.

  1. First, secure the Nest wiring mount to the wall. The Nest can go right on the wall without it, but you can use the included plastic wall plate to cover holes you don’t feel like patching. If the old thermostat was attached to an in-wall electrical box, there’s also an included steel plate. In our case, we're attaching the Nest right to the wall.

  2. Compare the wiring mount to your current holes. If, by some lucky chance, the mounting holes line up, just screw the base plate into those. Otherwise, put the Nest’s mount against the wall with the wires going through the center and mark where the new holes should be with a pencil.

    The Google Nest wiring mount
     Google Nest

    Make sure the plate is level. The base plate has a handy little level built right in, so if the bubble is directly in the middle of the level, you’re good.

  3. For drywall mounting, the Nest includes “self-tapping” screws, which means you can just screw them right in and they’ll (generally) stay secure. For hard surfaces, like wood walls, you should pre-drill mounting holes (use a 3/32 or 2.5 mm bit) at those marks.

  4. Put the base plate on the wall, line it up with your new holes and screw it to the wall. Again, make sure the wiring mount is level. The screws only need to be tight enough to hold the Nest snugly against the wall, so don’t over-tighten.

How to Connect the Nest Thermostat Wires

Conveniently, thermostat wires are color-coded (if yours aren’t, just refer to the picture you took earlier or stickers you applied).

In the regular Nest, there are multiple slots for certain colors (W1 and W2, for instance). Most homeowners just need to be concerned about the first one. The others are for more complicated, multi-stage/multi-zone (or system) HVAC set-ups.

However, if you’re installing the Nest E, the wiring plate is simplified to just the basic wires nearly everyone has.

  1. To place a wire, press down the button for each color, then slide the matching wire into the tiny hole so all the bare metal is hidden inside.

  2. Let go of the button and give the wire a very gentle tug to make sure it’s secure, then do the same for the rest of the wires.

    Google Nest Wired
  3. Of particular note is the blue C-wire, which provides power to the thermostat. Older systems might not have a C-wire, but the Nest has a wiring adapter that allows you to use it anyway. It’s included in the pricier Nest, but it's an extra purchase for the Nest E.

This is a cumbersome solution and we highly recommend having a C-wire for more than just convenience. Even with the wiring adapter, the power to the thermostat will still be uneven and add a slight bit of risk of malfunction to the thermostat and possibly your HVAC system as a whole.

How to Attach the Nest Thermostat

This is the easiest and most satisfying step. Once everything is secure and wired, it’s time to snap the Nest into its mounting plate.

  1. Align the thermostat with the mounting plate and press it to the plate so it locks on with an audible click.

  2. Now, turn the breaker back on and test your connections. If everything is correct, you’ll see a house appear on the Nest’s screen. Wait a moment and the set up will start.

    Home Again
    Success!.
  3. The Nest will then guide you through the set-up.

Unlike many other smart thermostats, the Nest doesn't have a touchscreen. You move through the settings by turning the dial right or left, and to select something, you press the face of the Nest like a giant button.