The Nest Learning Thermostat has been on the market for nearly four years now. One of the biggest things the Nest folks use as a selling point is energy savings. “Programs itself. Then pays for itself.” That’s the first thing you see when you go to the Nest homepage. But what do the data say? Three independent studies plus a white paper from Nest provide some answers. (GBA first reported on these three studies in a February 2015 news story.)
The first study was done on 185 Oregon homes that used heat pumps, and the study was conducted over one heating season (2013-14), with the report released in October 2014. Two nearly identical studies run by two different gas and electric utilities in Indiana looked at both heating and cooling in a total of 700 homes. The results were nearly identical, too. Finally, Nest published a white paper in which they analyzed the energy use of 735 Nest owners with gas furnaces and 624 Nest owners with electric cooling. (See links to all studies at end of article.)
Let’s take a look.
A study in Oregon
This one was focused on heating with heat pumps. The goal was to find a way to reduce the amount of electric resistance heat that typically is installed as a supplemental heat source in heat pumps. The Energy Trust of Oregon, which launched the research project, was looking for an alternative to their “advanced heat pump controls measure.” As I showed in my recent article on Michael Blasnik’s presentation on big data from Nest, there’s a lot of opportunity for savings in heat pump supplemental heating.
The Energy Trust installed the Nest thermostats in 185 homes, and 174 of those made it all the way through the study with the thermostat installed and working. The researchers…