https://www.cnet.com/news/amazon-echo-plus-costs-150-but-clearer-sound-more-bass-temperature-sensor-local-voice-control/

The integrated temperature sensor allows users to set up actions based on how hot or cool a room is. So if your bedroom hits 77 degrees, Alexa can send a notification to your phone and automatically turn on the fan. The Plus also comes with an equalizer feature; you can use your voice to adjust the bass and treble to customize your listening experience.

Amazon is giving the Echo Plus a new capability called Local Voice Control. It provides compressed Alexa controls locally in each device, so the assistant will still be able to turn the lights off even if your internet connection is down.