(You may have already
completed this step.)

Once you’re sure the power is off, remove your thermostat’s cover.

Some thermostat covers pop off, while others need to be
unscrewed. If you haven’t already, now’s a good time to take a picture of your current wiring.

(You may have already completed
this step.)

To get a custom wiring diagram for installation, simply follow Nest app’s thermostat installation instructions.

Important: This illustration is only an example. Each system’s
wiring is different. You must get your own custom wiring
diagram with our Compatibility Checker.

Incompatible wiring

High voltage wires

If your thermostat is labeled 120V or 240V or has thick wires
with wire nuts, your system is high voltage and isn’t compatible
with the Nest thermostat. Do not connect the Nest thermostat
to high-voltage wires.

 Stranded wires

Nest thermostats are not compatible with stranded wires. Do
not connect the Nest Thermostat to stranded wires.

Jumper wires are short wires between two connectors. The
Nest thermostat doesn’t need them.

Keep your current thermostat, the photo of your wiring, and any
jumper wires your current thermostat uses in a safe place.

That way if you ever decide to move and you want to take your
Nest thermostat with you, you’ll have everything you need to
reinstall your current thermostat.

Peel off the labels from the quick start card that came with
your Nest thermostat and attach them to the matching wires
on your thermostat. You can also use the white labels for
additional wires if needed.

Troubleshooting wire labels

If you have labels like W, Y, or R, use the wiring diagram that you
created earlier to choose which labels to attach to these wires.

If you have different wire labels not covered here, read this
article to learn more about thermostat wire labels:

If you removed your old thermostat without labeling your wires
first, check the picture you took in step 2. If you don’t have a
picture you can check your system to try to determine your wires,
or contact a Nest Pro.

Important: It’s important that the power to
your system is off to avoid blowing a fuse in your
equipment. If you blow a fuse, your
Nest thermostat won’t turn on, or may display
a power error after installation.

After removing the base, we recommend gently
wrapping the wires around a pen or pencil to
ensure they don’t fall back into the hole in the wall.

Now is a good time to patch and paint over any
holes in your wall. You can also use the included trim
plate to help hide scratches or screw holes on your wall.

Use the bubble level to make sure the Nest thermostat is level.

If you’re going to use the optional trim plate, place it on the wall
before installing the Nest base.

Tip: You can paint the Nest trim plate to match the color of your
wall. If you’d like to paint your trim plate, make sure to paint it
before it’s installed. Make sure not to get any paint on your
wiring, the Nest base, or your thermostat’s display.

Pull the wires through the center of the base, then attach it to
the wall with the screws.

Important: Use a screwdriver, not a power drill to drive in
screws for the Nest base. Drills can easily over-tighten the
screws and crack the base and damage its electronics.

Use the bubble level to make sure the Nest thermostat is level.

The Nest screws are self tapping, so there’s no need to drill into
soft materials. If you need to drill into harder things like wood,
use a 3/32 or 2.5mm drill bit.

Connect the wires to your Nest thermostat’s base by following
the wiring diagram that you got from the Nest app.

Press down on the connector button and insert the wire as far
as it will go in. Then release the button.

The connector button should stay down. This confirms that the
wire is properly seated.

Terminals with wires should stay pressed down.

If the button doesn’t stay down, take the wire out, straighten it,
and put it back in as far as it will go. You may need to strip the
end of your wire to make sure enough copper is exposed.

Important: Do not put more than one wire in each connector on
the Nest base.

Important: Do not connect any “spare” wires to your Nest
thermostat that were not connected to your old thermostat.
Only use the wires on your Nest wiring diagram.

After all the wires are securely connected, push them down
toward the wall to make sure they’re flush with the base. If your
wires stick out too far they can keep your thermostat display
from connecting properly.

If your wires stick out from the wall press them down

Before	After

After turning the power back on, your Nest thermostat should
power on automatically. If it doesn’t turn on, you might see a
blinking red light to indicate that the battery is charging.

Wait for the battery to charge or check this article for
troubleshooting steps: