Can I install one of these in my house and then connect more basic ones in other locations or do I need to install one of these in every location to be able to get the notifications?

Hi Taylor, thank you for reaching out! During an alarm, the SC5 can announce the location of the originating alert if a name was setup in the app, but this feature is supported only between SC5 and Nest Protect devices. Other wired interconnected alarms will still respond but will not announce locations. When an alarm is triggered, all interconnected detectors will respond, but you’ll only receive a push notification, banner, and full-screen alert from the device that originally detected the issue. If multiple detectors detect issues, each originator will send its own full alert.— Charlie