Programmable thermostats (PTs) can save energy. If a conditioned space’s temperature is automatically adjusted for when the occupants are not home, adjusted for bedtime conditions, and is allowed to rise in the summer or decrease in the winter, less energy will be required to cool or heat the house.
But because of human meddling, most programmable thermostats aren’t saving much energy. Overriding settings and then forgetting to turn the temperature back at a later date or failing to program settings in the first place is problematic. In fact, several studies by the Environmental Protection Agency and Department of Energy have led to the Energy Star label being revoked for PTs.
Most PTs are just a clock with digital switches. For a typical PT to work flawlessly, your life needs to be predictable. They are available with different configurations like 7-day (each day can be uniquely programmed); 5-2 (the weekend days are different than the weekdays); or 5-1-1 (Saturday differs from Sunday). But today’s PTs have more features, are much easier to program, and can be controlled via a Web portal or smartphone app.
Nest Learning Thermostat ($249; nest.com) programs itself by tracking user interaction and adjustment patterns, usage activity and temperature sensors, and monitoring weather. Change the temperature a couple of days in a row and the Nest will adjust its programming accordingly. It takes the Nest about a week to learn and set up a temperature protocol. You control the Nest by turning or pushing the outer dial in response to its full-color screen’s questions or prompts. You can also control the Nest remotely online.
Before you buy, visit the company website and answer a few questions about what thermostat wires you have and it will tell you whether or not the Nest will work with your HVAC system. You can buy the Nest online, or through Best Buy, where you can have it installed by their Geek Squad for $120.
Nest encourages do-it-yourself installation, even providing a screwdriver and all the mounting hardware for installation in any kind of wall, including cover plates if the hole left by your previous thermostat is too big for the Nest to cover. I was planning to install the Nest myself, but since I pre-ordered very early, they offered free installation. The tech was in and out in 25 minutes, and that included me picking his brain for this article. He had installed at least 100 already.
As for problems, he said that one came with a dead battery that he recharged via a USB cable from a laptop computer. He had also cleaned up after do-it-yourselfers, who had neglected to turn off the power to the furnace as directed in the manual. The 24-volt thermostat circuit hurt neither the do-it-yourselfer nor the Nest, but crossing some wires can burn out the HVAC transformer. The tech liked Nest Lab’s factory support, though he preferred the paper manual over the online version. I thought my Nest might be misbehaving and leaving the heat on at night, but in fact it was accurately sensing my insomniac house guest walking by on the way to the kitchen to make a pot of midnight tea.
It may be time to re-apply Energy Star ratings for PTs—at least for the Nest. While the newer and more expensive PTs are easier to program, only the Nest does the programming itself. It’s as close to idiot-proof as you can get.