Nest™ Learning Thermostats: Nest 2 versus Nest 3, what's the difference?
Amazon.com: Google Nest Learning Thermostat - Programmable Smart Thermostat for Home - 3rd Generation Nest Thermostat - Works with Alexa - Stainless Steel
Nest 2 vs Nest 3 – Is it Worth Paying a Little More? Find Out the Details