After two calls to Nest support they say my base unit has gone bad and that I need a new one, no they don't just sell that part I have to buy a whole new Nest Thermostat but they will give me a 20% discount if I buy if from their store. Why would I spend more than $200 to but a device that breaks after a few years from a company that really does not care about their customers. My old cheap thermostat was still going strong 14 years after I put it in. I only repklace it to upgrade to the Nest. Now I will be finding a product by a company that can make something that lasts more than a few years and who supports their customers.