How can you make a smart thermostat even smarter? The company behind the Nest thermostat says it's done that by improving how the device "learns" from the temperature adjustments owners make -- or don't make -- over time.
That enhanced auto-schedule feature is one of the key changes that Nest is rolling out to its Wi-Fi-connected thermostats this week. The company says smarter, automatic scheduling of temperature adjustments can help owners save up to 6 percent more than before on their heating and cooling costs.
The updated Nest software also adds a Quick View feature that lets users check outdoor weather conditions, energy use history and coming scheduled temperature adjustments. And new support for system testing is designed to help users identify and resolve potential problems with the thermostat.
A 'More Holistic View'
One common problem with programmable thermostats is that users find it too difficult to set a temperature adjustment schedule that's best adapted to their daily and weekly behavior patterns, Nest notes in a new white paper released this week. As a result, many people leave their thermostats in a "hold" mode that is similar to an unprogrammed thermostat, which means they don't gain any significant efficiency in heating or cooling or savings on their energy bills.
Nest says its new enhanced auto-schedule feature aims to avoid that problem while still leaving users in full control of their household temperature settings. Using an updated algorithm based on customer feedback and data analysis, the new Nest auto-schedule takes into account any changes the owner has -- or hasn't -- made over time, and "learns" to make automatic adjustments based on that behavior.
That improvement also avoids an ironic reality about "smart" thermostats, which is that users do not like devices that adjust temperatures to settings they did not choose. In fact, studies have found that homeowners with thermostats that do this frequently end up adjusting household temperatures in ways that actually increase, rather than decrease, energy use.
"Every interaction is treated as a way for the user to communicate with the device about his or her preferences for a particular temperature at a particular time and day of the week,” Nest said. “In addition to considering active interactions, we also consider lack of interactions (indicating satisfaction with the current temperature), as well as the room temperature and whether the user is home or away. This provides a more holistic view of user preference than was considered previously."
New Time, Weather Support
Nest, which was purchased by Google for $3.2 billion in January, said this week's software update was the first major redesign of its auto-schedule feature. It added that tests have shown the enhanced auto-schedule feature can reduce cooling costs by a total of 23.1 percent and heating costs by 19.5 percent, which represents an improvement of about 6 percent when compared with a "flat" temperature schedule on the thermostat.
"When your schedule shifts -- like when summer's over and the kids are back at school -- Nest can now catch on faster that the temperature adjustments you're making are part of a new pattern rather than just one-off changes," Nest founder and head of engineering Matt Rogers wrote in a blog post on the company's Web site Tuesday.
While the efficiency improvements Nest has reported are based on data from homes in North America, the company says it believes household savings in Europe will be similar.
Rogers said this week's update also adds time and weather support for customers in many other countries, and added that the company is already working on its next update.