There are many different brands, models, and types of central air conditioning systems. Each model has unique features and energy efficiency ratings. However, all central ACs have one thing in common: They all use electricity, not gas. Of course, your electricity is sourced from your local power company. If you are concerned about your family’s carbon footprint, then you should assess the power source for your local utility company.In Tucson, many customers rely on Tucson Electric Power (TEP) for their power. TEP formerly used coal to produce electricity. Coal is a heavy polluter and a major factor in driving climate change. However, in 2015, TEP announced that it was ending the use of coal at its largest power plant. This move was planned to allow TEP to become more environmentally responsible. In addition, it helped Pima County make the transition to stricter ozone standards. Instead of coal, TEP is now relying on natural gas, which is far less harmful to the planet than coal.