The United States Environmental Protection Agency (EPA) regulates the use of AC units to reduce the environmental impact caused by their functioning. One of the key regulations is the Energy Star program, stating that an Energy Star-certified window AC consumes about 9% less energy than standard models.
One of its guidelines also mentions the safe disposal of HVAC equipment, as they contain refrigerants and other chemicals that can harm the environment. As such, EPA recommends proper recycling and disposal at designated facilities instead of dumping your old ACs in landfills.