In most cars that are on the road today, R134a refrigerant makes the A/C system blow cold on hot days. Selected for its low flammability and safety, as well as because it’s kinder to the environment, almost every car built since 1994 is equipped with R134 refrigerant.

R1234yf was chosen to replace R134a in all new cars by 2021. Some manufacturers have already made the switch, or the switch is in progress.

This new refrigerant performs similarly to R134a, but with one important difference: it breaks down much faster in the upper atmosphere. That means it’ll contribute less to global warming. It’s also easy to upgrade a car’s A/C system from R134a to make it compatible with R1234yf