What is geofencing and how do smart thermostats use it?

Your smart thermostat can use your phone’s location to figure out if you’re home or not.

What is geofencing?

Imagine an invisible border surrounding your home. When you’re “inside” the border you’re considered to be “home”, so your thermostat makes things nice and comfy for you. When you’re outside that boundary, your thermostat lets the home’s temperature rise (or fall) a bit to save you some money so you don’t cool or heat an empty place.

Who is it for?

Geofencing is ideal for people who are in and out all day, or don’t follow a set schedule day-to-day.

For those people, geofencing can be a useful feature that takes some of the effort out of adjusting the thermostat. Let it figure out when you’ve left and when you’ve returned, and take all the effort out of trying to develop a schedule that suits your unpredictable days.

Even better, geofencing isn’t limited to just thermostats: many sophisticated smart home hubs exist to control all of your home’s smart devices based on whether you’re home or not.

What do I need?

Typically, you use your smartphone as your “geofence” device, since it’s likely to be with you most of the time. But in order to work, you’ll need to make sure a few settings are kept on at all times:

Wi-Fi should be ON
General location services should be ON
iOS: keep background app refresh ON
Android: turn location services to “high accuracy”
Airplane mode should be OFF

If anyone in your family doesn’t have an iOS or Android phone, or doesn’t have cell service on their device, geofencing may not work for them.

Which thermostats offer geofencing?

Nest

Nest calls its geofencing “Home/Away Assist”, a clunky name that’s meant to invoke a certain level of intelligence in your Nest-brand devices. They figure out when you’re home (or away), and “assist” by adjusting the temperature accordingly. (In the winter, that means letting your home get cooler while you’re gone. In the summer, that means letting it warm up. This saves you energy and is supposed to be more or less invisible to you, since it happens when you’re away.)

We think Nest has the best implementations of geofencing on the market right now, namely because it supports multiple accounts (one per member of your household) and can track all of them simultaneously. When the last person leaves, it goes into “away” mode. When the first person comes back, it goes back into “home” mode. When you set up your Nest account, you can enable the Home/Away Assist feature and assign it a device to watch. You can only assign one device per account (but you can associate multiple accounts with your home). Nest uses a combination of cell and WiFi data from your device to figure out if you’re home and raises/lowers the temperature accordingly.

Nest geofencing perks

Nest geofencing drawbacks

Support for multiple individual accounts in a single “family” – no need to share login information, along with certain permissions for individuals
“Away” mode can kick off away settings for all your Nest devices – Nest Protect, Nest Camera, etc.
Supported by both Nest Learning Thermostat (flagship model) and Nest Thermostat E (budget model)

Some users report it conflicting with the schedules they’ve created
Might interfere with “Learning” feature if your coming and going during the learning period isn’t typical
Only works with Nest products, not other home automation devices (such as Hue bulbs)
You cannot adjust the geofence radius, which might be useful for cases such as heading home from 50 miles away or working just 2 miles away

Read our detailed review of the Nest Learning Thermostat

Ecobee

The impression we got from playing around with ecobee’s geofencing feature is it’s kind of a mess right now.

To use Ecobee geofencing with an Android phone, you can configure it through the ecobee app itself. This works great for my partner, but not for me – I’m on iOS.

To use it with an Apple (iOS) phone, you have to configure it through Apple’s own HomeKit app, which requires a hub (such as an Apple TV, a HomePod, or an iPad that stays home all day). While I have an Apple phone, I don’t have any of the other devices, so I wasn’t able to get into the ecobee geofencing party myself.

Assuming you do get the geofencing set up, you might be surprised to find that it doesn’t really coordinate with the temperature/motion sensors that helped make ecobee so popular in the first place. If you and your phone are set up with ecobee’s geofencing, and you leave (taking your phone with you) and go out for the day, but someone else stays home, their motion won’t be enough to keep the ecobee in “home” mode – the geofencing setting will prevail and they’ll be left cold (or sweating).

Furthermore, the ecobee geofence triggers seem to act like “holds” rather than a return to schedule. Paul Quinn over at androidpolice.com reports this issue in greater detail. Later, we found that if we set up the geofence trigger to “Resume my schedule” upon returning home, it would go back to that schedule – even if the scheduled thing was a temperature setting you’d normally want to use when you’re not home – which could be interrupted by walking by a sensor to tell the ecobee you’re actually home so it adjusts to a temperature you’d normally want when home.

At this point, we threw our hands up – this is just way too much overhead for a thermostat, something that should be effortless and almost completely out of mind. We love ecobee, but we ran into a lot of frustrations trying to use this specific feature. And, apparently, so did a lot of other people – so many, in fact, that ecobee themselves suggests ecobee users rely on IFTTT and Life360 to manage geofencing and their products.

We did not try either of these solutions ourselves, but it’s easy to find other people recommending them. You need both, and they are both free. Life360 (on the phones of everyone in your household) keeps track of where you all are. Now you just need two IFTTT recipes: one to set your ecobee to “Away” when the last person leaves the home, and another one to set your ecobee to “Resume program” when the first person returns home. Once set up, most people seem pretty happy with this combination. (We’ll try it ourselves at some point in the future, but for now, IFTTT and Life360 seems to be the way to go for ecobee owners.)

The Smart Cave has a detailed guide for getting started with IFTTT and Life360 with an ecobee thermostat.
More help with enabling ecobee geofencing through Apple HomeKit, Android, or IFTTT

Ecobee geofencing perks

Ecobee geofencing drawbacks

Might work better for people with unpredictable schedules and people who are in/out of the house all day
Using IFTTT and Life360 (you need both, and they’re free) seems to create the optimal ecobee geofencing experience (here’s a good guide)
Use instead of pre-programmed “Away” settings

Ecobee’s innate geofencing is kind of sucky and conflicts with schedules you might’ve set up or room sensors you might have throughout your home
Ecobee’s innate geofencing requires additional equipment if you’re on iOS (such as an AppleTV or iPad at home all day)
Ecobee’s innate geofencing takes precendence over motion detected by the room sensors (ie: if you leave, but your spouse is still home sitting in front of a motion sensor, the geofence settings will prevail and the thermostat will enter “away” mode)
Puts your home in “hold” mode, rather than resuming the current schedule (you have to flip it back to the intended schedule once you’re home, a seemingly unnecessary step)

Read our detailed review of the ecobee4

Sensi

Sensi’s geofencing is like a circle with your home at the center. The circle is 3 miles in radius, and when you’ve gone 3+ miles away from home home, the Sensi will signal to your thermostat to raise or lower the temp accordingly. (By default, that means lowering the temperature by 3 degrees in heating mode or raising it 3 degrees in cooling mode.) Once you get back inside that 3-mile zone, the thermostat returns to the originally selected temperature. Read more about Sensi geofencing here (sensi.com)

Sensi’s geofencing feature is quite basic – you’re either in the 3-mile radius or you’re not, and every member of your household has to share the same login credentials in the app in order to take part in the geofencing. There is currently no way to adjust the 3-mile radius. Basic’s not so bad, though – after all the craziness we went through trying to get geofencing working with an ecobee thermostat, we have a renewed appreciation for basic.

Sensi geofencing perks	Sensi geofencing drawbacks
Might work better for people with unpredictable schedules and people who are in/out of the house all day Works with or without a pre-programmed schedule	All members of the household must share one account, and any of those people can disable the geofencing or alter the existing schedule Only works with Sensi thermostat, not other home automation devices (such as Hue bulbs) The geofence radius is locked at 3 miles, which for many people will treat them as being at home even though they’re at work, school, or running errands around town

Read our detailed reviews of the Emerson Sensi and the Emerson Sensi Touch

Other ways to achieve geofencing with your smart thermostat

Rather than configuring individual devices to manage automation, you can link all your smart home devices to a hub and control things through that.

The extra setup steps are worth it – most people seem to be happy with the end result.

IFTTT and Life360

We discovered the IFTTT/Life360 combo when trying to get geofencing working with our ecobee.

Both are free, and the setup is pretty straightforward. Life360 follows all of your family’s phones (up to at least a couple dozen) and you can customize multiple fences, ie: around your home(s), work, school, etc. Make the fences as big or as small as you want, and set up triggers that work for all of your smart home devices, such as light bulbs, cameras, and thermostats.

In the context of a thermostat, you can use IFTTT recipes to do the following:

When last person leaves the home fence, set thermostat to “Away”.
When first person re-enters the home fence, set the thermostat to “Resume Program”

Here’s a page of steps to help with connecting IFTTT to Ecobee, since ecobee’s built-in geofencing leaves something to be desired, but IFTTT is compatible with nearly every smart thermostat on the market right now. If you get set up with IFTTT and Life360, you can use it to control nearly any WiFi enabled thermostat on the market right now. We think this is the way to go – it’s free, easy to set up, and compatible with virtually everything.

HomeKit

HomeKit is another way to automate your thermostat and set it up with geofencing, and it lets you do some pretty neat things (ie: talk to Siri and ask her to raise or lower the temperature) but this one comes with so many caveats we hesitate to recommend it:

It’s only for iOS users
You have to have a HomeKit hub somewhere in your house (such as a Mac computer running Mojave as of this summer, or an AppleTV 3 to follow one phone, AppleTV 4 to follow more than one phone, or an iPad with iOS 10 or later that basically stays home all the time)
It doesn’t work with Nest products

If your family is entrenched in the Apple ecosystem and loves it there, by all means – check out HomeKit. (We haven’t used it ourselves.)

SmartThings Hub

Samsung’s SmartThings Hub (which we have not personally used) is an oft-recommended smart home management device. It supports geofencing natively, and may do a better job of handling geofencing for a thermostat than the manufacturer’s own app. Also, SmartThings lets you control virtually any WiFi-enabled smart device, such as smart lightbulbs, home cameras, smart outlets, and more.