The Nest can turn itself off while you’re at work, so it only heats or cools your house when you’re at home. If it doesn’t guess when you get home correctly, though, you could be waiting hours in an uncomfortable house. If you have an Automatic Pro, your car can tell Nest to start warming up as soon as you leave work.

RELATED: How to Make Your Car Smarter with an OBD-II Adapter

Automatic Pro is a pretty awesome smart car system that uses your car’s OBD-II port to communicate with your phone and a bunch of other services like Nest. The Nest integration for Automatic Pro allows you to “pre-condition” your home as soon as your car leaves a specific area like work.

Preconditioning is slightly different from Nest’s normal Home/Away Assist, and it’s unique to Automatic. Instead of turning on your heater or air conditioner right away, preconditioning will only heat or cool your home long enough to be comfortable when you get home. So, for example, if your commute home is an hour, but it will only take twenty minutes to heat your home, your Nest will only turn the heater on when you’re twenty minutes away from the house.

To connect your Automatic Pro to Nest, head to the Nest app on Automatic’s site here and click Connect To Nest.

Next, log into both your Automatic and Nest accounts.

Once you’re logged in, you’ll see a control panel with a list of sample rules that you can customize. Each one is disabled by default. You an either create your own rule or customize the existing ones. For our guide, we’re going to create a new rule. Click Create a New Rule at the bottom of the page.

At the top, give your rule a name like “Precondition my home when I leave work.”

The left-hand panel has several conditions to determine when this rule will activate. In our case, we want it to activate whenever your car is turned on near work. You can narrow down this rule by time of day later, so it won’t activate when you leave for lunch, for example.

First, under Automatic Event, choose Ignition On. Next, enter your address in the Of Address box. You can narrow or widen the geofence around your work address with the “Or within” dropdown box. For example, if your work address is in a single building, you can set the within distance to a couple blocks. If your work address is a campus, you can set it to activate if your car turns on within one mile of your work address.

In the middle panel, you can choose the days and times this rule should activate. Check the box for every day of the week that you work. You can also set a time frame that Automatic will monitor. For example, if you drive your car to lunch every day, you may want to set this rule to only activate between 4:00PM and 8:00PM when you usually head home, rather than all day.

In the final panel, you can set which actions you want your Nest to take whenever the rule is activated. Under Nest Structure, choose which thermostat you want to turn on or off.

The Nest Event drop down is where the real magic happens. The “Set to Home” and “Set to Away” options work just like they do in the Nest app. “Precondition for ETA,” however, works a little differently. This will calculate how far your work address is from home and turn your heater or air conditioner on in time for you to get home. Choose this from the dropdown. You’ll see a new Home Address box appear. Enter your home address here.

Once you’ve entered all this info, scroll down and click Save.

Automatic’s Nest app gives you a lot more fine-grained control over when your Nest thermostat is turned on and off over the basic Nest app. Set it up once, and you’ll always have a comfy home waiting for you when you get home from work.

Profile Photo for Eric Ravenscraft Eric Ravenscraft
Eric Ravenscraft has nearly a decade of writing experience in the technology industry. His work has also appeared in The New York Times, PCMag, The Daily Beast, Popular Science, Medium's OneZero, Android Police, Geek and Sundry, and The Inventory. Prior to joining How-To Geek, Eric spent three years working at Lifehacker.
Read Full Bio »