Middle school students need to know about energy concepts and how they can reduce their energy use. New energy-monitoring tools provide powerful opportunities for students to engage in authentic investigations rich in the science practices described in "A Framework for K-12 Science Education" (NRC 2012), while at the same time advancing their knowledge about energy and learning the mathematics of data that describe change over time. Analyzing, interpreting, and basing decisions on the wealth of energy data increasingly available to homeowners is rooted in mathematical, scientific, and communal questions. Herein lies the challenge--in terms of mathematics, middle school students often have difficulty with the related processes of measuring, visualizing, analyzing, and interpreting data. They may have learned units of measurement without understanding what they mean, and have typically learned to plot data points on a graph without understanding how a graph helps a person "tell the story of the data." This article discusses energy-monitoring activities for middle school math and science, as well as their impact on students' learning. (Contains 2 figures and 7 online resources.)