| In ordinary conversation, when the term air | | | | air. In the early stages of its development, air |
| conditioning is mentioned, people automatically | | | | conditioning units used harmful gases such as |
| take it to mean cooling room temperature. | | | | ammonia and methyl chloride as refrigerants. |
| Technically speaking, though, air conditioning is the | | | | They were soon replaced by another type of |
| process of controlling room temperature through | | | | chemical, the patented substance called |
| various means that involve ventilation, heating and | | | | Freon.Freon is safe for humans. However, it is |
| cooling. In construction, it is referred to as | | | | harmful to the environment. When released into |
| HVAC.In 1902, The New York Stock Exchange | | | | the atmosphere, this chlorofluorocarbon gas is |
| was the very first building to use air conditioning | | | | believed to be a contributing factor to the thinning |
| units that separately cooled and heated the air. | | | | of the ozone layer. Most air conditioning units sold |
| Later that year, Willis Havilland Carrier installed the | | | | today still use this type of gas, particularly the |
| very first electrically-run air conditioning unit at a | | | | HCFC R-22. It is said that environmentalists will |
| printing plant. The unit not only cooled the air but | | | | have to wait until 2010 to see the total |
| also controlled the humidity.In those times, air | | | | eradication of HCFC R-22 in air conditioning |
| conditioning was mostly used in manufacturing | | | | untis.Air conditioning units have different types of |
| facilities to improve products by controlling the | | | | refrigeration cycles. The first type uses a heat |
| effects of humidity, thus, increasing employee | | | | pump that drives out hot air from the room and |
| productivity. It was several decades later, in the | | | | blows in cooled air though a compressor. The |
| 1950s, that homes and automobiles started to be | | | | second type pumps in a refrigerant. When the |
| fitted with the air conditioning technology.An air | | | | refrigerant evaporates, it takes with it the hot air |
| conditioning unit cools the air through a refrigerant, | | | | and leaves cooled air. |
| a substance that alters the temperature of the | | | | |