To measure waste heat leaving a home, a special Thermal Infrared (TIR) camera flown late at night (long after the sun has gone down) from a low altitude aircraft, records invisible heat. This is known as thermal infrared energy. Images from this camera can be analyzed as different temperatures (Fig 8: white - hot homes, grey - vegetation, and black - cold roads), which can then be shown as pseudo colored HEAT Maps (Fig 8: red is hot, yellow/orange is warm, and blue is cold).