They bury it slightly, but in the FAQ: "The primary energy for HomeCool™ is derived from clean open flame burn of natural gas. This can be converted with an op

They bury it slightly, but in the FAQ: "The primary energy for HomeCool™ is derived from clean open flame burn of natural gas. This can be converted with an optional kit to propane and also hydrogen* (*once commercially available)." It burns gas. It may work in a similar manner to absorption refrigerators often found in RVs. https://en.wikipedia.org/wiki/Absorption_refrigerator https://en.wikipedia.org/wiki/Absorption_refrigerator Burning gas isn't exactly a clean energy source. In fact, we need to be aggressively exploring ways to stop burning gas for heating - not starting to burn more for cooling!