A thermostat can be such a simple device—so dumb a device if we’re feeling 21st Century snobby—that a strip of metal coiled up with a droplet of mercury at the end can do the job. The coil contracts as it cools, the mercury shifts to touch two wires and close a circuit, and on goes your furnace. Prefer a different temperature? Rotate the coil.
Simple is great, but that dumb device is responsible for a huge portion of your energy bill. That means constant adjustments are necessary if you want to avoid wasting energy overheating your house while you’re tucked into bed or away at work. This is the part of the story where the programmable thermostat walked in, offering automation in exchange for up-front fiddling. But a surprisingly large percentage of people with programmable thermostats don’t actually program them. In fact, the US EPA stopped offering “Energy Star” certification for programmable thermostats entirely in 2009 because their real-world impact was so unpredictable.
That's a problem, but the Nest Learning Thermostat has gained a following in the last few years by offering a solution—it programs itself as you turn it up or down throughout the week. The very same smarts that allow the device to program itself open other doors to efficiency as well. And at the company's Palo Alto offices, this seems to be just the beginning. Today, Nest is still working on its flagship device to make homes more energy-efficient.