Question: how to tell the difference between nest 2 and 3?
Answer: Nest 3 has a higher resolution screen than the Nest 2. The Nest gen 2 does not support Bluetooth or WiFi 5Ghz; Nest gen 3 supports both. Nest 3rd generation has safety alerts and Farsight; Nest 2nd generation does not. Nest 3 has five more sensors than the Nest 2.