Since the 1950s, Freon (R-22) has been the industry standard for air conditioning refrigerant—a substance needed for an HVAC system to cool the air. Unfortunately, it’s also damaging to the environment. The Environmental Protection Agency (EPA) enacted an R-22 phaseout, and by 2020, Freon will be illegal to produce or import. Refrigerant is expensive now, and it’s only getting pricier as the 2020 R-22 phaseout looms. Here’s what you need to know now.