How Automotive Air Conditioning Works

Recharging a Car's AC
An assortment of automotive air conditioning gauges
An assortment of automotive air conditioning gauges
Thinkstock/Comstock Images/Getty Images

Most of us start seeing ads in the spring for car repair shops offering deals on recharging your car's air conditioning in time for the coming summer. Which makes us ask, what is recharging the AC? Is it required, like an oil change? Does my car's air conditioning need to be recharged? Is this another scam that repair shops can pull on unsuspecting customers?

The answer to that last one is definitely no; recharging the AC is not a scam. It simply means that fresh refrigerant is added to the system. If the refrigerant is a bit low, it can be topped off, the same as if you were a bit low on oil in the engine. If it's really low, though, whatever refrigerant is still in the system needs to be drained out and replaced. This process of clearing out the system and adding new fluid is called recharging.

In either case, you've lost some refrigerant, which isn't so great. Even though R-134a is better for the environment than Freon, the Environmental Protection Agency would rather not have any air conditioning refrigerant leaking into the soil and rivers. If you're going to have the system drained and recharged, the EPA recommends having the technician take a look at the system to find the source of the leak and fix it. They don't require the repair, but they'd really, really like you to have it done.

This article has talked a lot about R-134a as a replacement for big, bad Freon, but there are others that have been approved by the EPA, too. R-134a has the distinction of being the refrigerant most tested and recommended by manufacturers, but there are others with names like Free Zone, Freeze 12, and Kar Kool that the EPA will allow in automotive air conditioning systems [source: EPA].

Related Articles


  • Automobile Magazine. "Automotive Air Conditioning History." July 2010. (Feb. 1, 2012)
  • Family Car Parts. "Automotive Air Conditioning Systems." (Jan. 25, 2012)
  • "How Air Conditioning Works." (Jan. 25, 2012)
  • "How Refrigerant Flows through the System." (Feb. 1, 2012)
  • All About Auto AC Systems. "Orifice Tubes and Expansion Valves." (Feb. 1, 2012)
  • Environmental Protection Agency. "Recharging Your Car's Air Conditioner with Refrigerant." Aug. 19, 2010. (Feb. 1, 2012)
  • Environmental Protection Agency. "Substitutes in Motor Vehicle Air Conditioners." Oct. 7, 2011. (Feb. 2, 2012)