Nest thermostat: thermal intelligence for your home
by Ethan Goldman, Energy Informatics Architect
We Vermonters spend a lot of money to heat our homes in the winter, and most of us would love to know how to save by keeping more heat in the house where it belongs! But it’s hard to know how to start saving energy if you don’t really know where that energy is going, and measuring thermal performance can be tricky.
We are starting to be able to use smart meters to better understand how we are using electricity. But the smart meters that allow you see your hour-by-hour electricity use are just one example of how intelligent, connected devices can help us understand and improve how our homes work. We may soon be able to use Internet-connected thermostats as a smart meter for our home heating systems.
One such device, the Nest thermostat, is not only an easy way to control your heating (and cooling) systems so you can save energy; it is also an Internet-connected home temperature monitor. As an energy data geek, I see the Nest as a way to measure energy performance. I was particularly excited when the Nest hit the market two years ago, because I was already developing a small research project to use temperature data from homes to measure their energy performance! I hoped to show how a homeowner could use the energy performance rating to estimate how much energy could be saved if they weatherized their home or changed thermostat settings. This would allow homeowners to check the rating before and after making home energy improvements to see how much energy was actually saved.
Testing it out in the real world
The study began in 2012 and included the installation of 19 Nest thermostats in 15 homes. Once the data started flowing, my team and I developed a way to measure how fast energy leaks out of the house. As might be expected, every house cools off faster when it’s colder outside. However, some houses hold heat better at low temperatures than others. Using data from the Nest, we calculated a simple rating for each house based on how it performs at different temperatures. We still need to rate many more homes, because we would love to show people how their home compares to similar homes.
Now we’re embarking on phase 2 of this study, allowing hundreds more Vermont households to participate.* You can volunteer to join Phase 2 by calling 888-921-5990 or emailing info@EfficiencyVermont.com.
*This study is no longer open.