I recently set up two ecobee4 smart thermostats in my home. I choose ecobee over nest because of the native Homekit integration. The overall installation was not too difficult since I had existing C-wire’s in both of my units.
One of the biggest features smart thermostats give you over a standard thermostat with a schedule is the ability to know whether you are home or away. They can do this by using the built-in motion sensors which exist in the thermostat and remote temperature sensors or a geofence using your phone’s GPS. Geofence is my preferred method because if someone is home and decides to take a nap, the thermostat could go into away mode while geofence knows your true location and can set the thermostat in Home or Away mode.
Since my family only uses iOS devices, Homekit made geofence possible but it was a little complicated to set up. First off, geofence and automation require a smart hub using an Apple Tv 4k, Apple Homepod or iPad. Next, enable Homekit on your ecobee using the ecobee app but don’t enable geofence within the app. The geofence option inside the ecobee app will only allow one iPhone to control whether the system is in Home or Away mode. Once Homekit is enabled, go to the Home app on your iPhone device and invite other family members to your home. Also, make sure you enable the Allow Remote Access and Allow Editing for each family member. Next, go to the Automation tab and add new automation for when people arrive and people leave. The key is to set up the ecobee scene for Arrive Home to be When Anyone Arrives Home and the Leave Home scene to be triggered When The Last Person Leaves Home. This will make sure the thermostat will only go to Away mode when nobody is home.
Most of the guides that describe how to get geofence to work with multiple family members require the use of multiple apps such as Life360 and IFTTT. This seemed overly complicated and prone to error. If your family uses iOS devices you should be able to follow the steps above to setup multiple family member geo fence with the ecobee. I have been using this setup for several days and it has worked flawlessly. Hope these steps help you get your ecobee setup!