umming air conditioners are the soundtrack to summer in the U.S., given that use them for cooling.
Even though , however, many people still have questions about exactly how it works, how to use it best, and how it affects air quality, , and the environment. TIME spoke to experts to get answers. In the most basic terms, “an air conditioner absorbs heat from the building and dumps it to the outside,” explains Jeffrey Siegel, a professor of civil engineering at the University of Toronto who researches ventilation and indoor air quality.
More specifically, a compressor moves liquid refrigerant into an indoor coil, where it evaporates and pulls heat from the surrounding air. The gaseous refrigerant then flows to the system's outdoor coil, moving heat out of your home. The gas condenses back into a liquid in the system’s outdoor coil, and the process starts again.
Central air-conditioning systems, window units, and mini-splits (which usually sit high on the wall) work in conceptually the same way, but there are differences in how they’re installed and exactly how they transfer heat. Functionally, the biggest difference for consumers is that central systems cool an entire home, whereas window units and mini-splits are designed to work in only one room. It depends on what kind of system you have.
Window units and mini-splits typically don’t have high-quality filters, so they don’t do much for air quality beyond temperature regulation, Siegel says. Central air-conditioning.