Home air conditioners work by removing the heated air and humidity in the room and replacing it with colder air. You can think of a home air conditioner as a type of refrigerator. They create the cold air through direct expansion coils or chilled water coils as the warmer air is blown across them. The refrigerant used in home air conditioners can vary from unit to unit.
This type of refrigerant has been banned since 1995, but is still commonly used in older air conditioner units. It causes respiratory problems and problems to the ozone layer. The refrigerant will last more than 30 years before dying out.
This refrigerant has a much smaller lifespan and consist of methane or ethane in combination with chlorine and fluorine. While they are less destructive to the ozone layer, it is only considered a temporary refrigerant until a non-chlorine type can be developed.
Refrigerant blends are becoming more and more prevalent in home air conditioners today. They are environmentally friendly, but do have one drawback. The cost of an air conditioning unit with this type of refrigerant is much higher than traditional units. However, the price will drop as more and more manufacturers begin using refrigerant blends.