Nest includes everything you need to attach the doorbell to your house, even a huge drill bit in case you have to drill into stucco siding. If you don't want to attempt the installation yourself, the company can connect you with a Nest Pro. But if your existing doorbell's power supply is up to snuff, the process isn't terribly complicated. Facial RecognitionUnlike most video doorbells, the Nest Hello has facial recognition technology. Once you teach it the names of frequent visitors, the companion app available for both Android and iOS will start to name them in the push notifications. The Nest Hello gets big points for including a snapshot from the camera with each notification, so you can get a glimpse of what's happening without having to open the app. The snapshots are extra handy when facial recognition is wrong — which didn't happen often, to be fair. First, the app asked me to identify my family and close friends multiple times from photos the Hello took. You can do this for anyone who comes to your door. I tagged my husband four times, for example, and my son six times. In the Nest app's Familiar Faces gallery, you can tap Select, choose all the instances of the same person, and tap Merge to combine them.