Big Data in a Little Package

This post, written by CEGA affiliate Lucas Davis, was originally published on The Energy Institute Blog.

Temperature loggers can help us build more energy-efficient homes.

One billion (yep, 1,000,000,000) new homes will be built worldwide by 2025. How do we make homes that will stay cool in the summer? Stay warm in the winter? How much does insulation help? What about passive cooling systems? Window shading?

Temperature loggers can help answer these questions. This LogTag Trix-8, for example, costs about $25 and can record hourly temperatures readings for almost a year.

Note: The LogTag Trix-8.

We used hundreds of LogTags in a new project testing energy-efficient homes in Mexico. The LogTags worked flawlessly, generating rich high-frequency data about thermal comfort and facilitating statistical tests comparing homes with different features. I see great potential for using temperature loggers like these in similar projects. If we are going to make homes as energy-efficient as possible, we need to test what works and doesn’t work, and loggers can help.

Better, Cheaper

Temperature loggers have been around for a while. But, like most digital technologies, they keep getting better and cheaper. For our project we tested seven different models of loggers made by five different companies (Rotronic, LogTag, HOBO, Newsteo, and iButton). We selected the LogTag because it was particularly easy to use but our overall experience was positive with all models.

Note: Here are four of the other loggers we tested. It is hard to get a sense of scale from these images but the iButton temperature logger, far right, is much smaller than the others, about the size of a thick U.S. dime.

To access the data, you use a cable to connect the LogTag to a laptop. We tested other models that use radio and Bluetooth, but decided against the wireless approach because it costs more and because, in our case, real-time feedback was not particularly important. That said, my colleague Catherine Wolfram is working on a new industrial energy-efficiency project with wireless meters, and the ability to do continuous monitoring and real-time feedback is very compelling in many settings.

The Project

We conducted the field experiment near Monterrey, Mexico. We provided 230 new homes with free wall and roof insulation and other energy efficiency upgrades, and we compare them to another 230 homes without upgrades. For both the upgraded and non-upgraded homes, we installed temperature loggers in the homes’ living rooms, and collected data over 16 months. The complete results are available in an Energy Institute working paper (available here coauthored by Sebastian Martinez and Bibiana Taboada).

Note: Long rows of nearly identical homes, with a mix of upgraded and non-upgraded homes.

Before I get to results, I want to step back for a minute and say why I think this is important. Buildings are responsible for more than one-fifth of global energy consumption and energy use from buildings is expected to increase 32% by 2040. We’ve learned a lot about how to build energy-efficient buildings but, as always, it is important to continue validating technologies using real data on outcomes.

Focusing on new buildings also makes a lot of sense. We know from Energy Institute research that it is very expensive to retrofit existing homes, so wouldn’t it be cheaper and easier to make homes energy-efficient the first-time around? In our study there are long rows of nearly identical homes, allowing for significant economies of scale in construction.

To read the complete blog post, see here.