A: How does THIS determine the inside temperature? Its a thermostat. It has sensors. How do YOU determine the indoor temperature? Look at the display on the thermostat.
A: Hi there, per our vendor, this Learning Thermostat, 2nd Generation does not have an estimated arrival for Homedepot.com at this point. However, if you would like to be notified with updates on the status of this item, you can enter your email address into the field provided on the product's page. We appreciate your business and look forward to serving you in the future. Thank you for shopping Home Depot!
A: Obviously faster is better. That said, you connect to your thermostat through their dedicated server, so all you need is a connection. Speed isn't really an issue.
A: Best explained by NEST. https://nest.com/support/article/When-Nest-needs-a-common-C-wire