Have you ever started your car on a hot day only to find that nice cold air you were expecting to come from the vents was hotter than outside? You lost your air conditioning and now you know what a big difference a little cool air makes. A good functioning air conditioning system should produce temperatures between 40 and 55 deg., while some even will go as low as 30 deg.
When I began working on AC systems back in the early 70’s we were using a refrigerant called R12 and you would come on down to the garage and we would “top off” your “Freon”, and if was a small leak, you were good until next spring. But around 1994 the government suspected R12 was causing problems to the ozone layer because it’s a chlorofluorocarbon and by filling the system every year, all of the Freon was eventually entering the atmosphere and was no longer an option. The government suspended all R12 production and came up with guidelines for a new type of refrigerant named R134 and is still used in most vehicles through the 2014 model year. Now the government changed the guidelines again to the new R1234yf refrigerant for all new vehicles built in or entering the US. By federal, law all persons working on an automobile AC system for favor (compensation) must be certified to handle any type of refrigerant including R1234yf.