In 2007, Google unleashed a fleet of cars with roof-mounted cameras to provide street-level images of roads around the world. Now MIT spinout Essess is bringing similar "drive-by" innovations to energy efficiency in homes and businesses. The startup deploys cars with thermal-imaging rooftop rigs that create heat maps of thousands of homes and buildings per hour, detecting fixable leaks in "building envelopes" -- windows, doors, walls, and foundations -- to help owners curb energy loss. About the size of a large backpack, Essess' rig includes several long-wave infrared radiometric cameras and near-infrared cameras. These cameras capture heat signatures, while a LiDAR system captures 3-D images to discern building facades from the physical environment.