A/C Pro

What is Refrigerant? And Other Questions Nobody Asks

Refrigerant is one of those things you use all the time but don’t really think about. It’s used in every car air conditioner, refrigerator, freezer, and water cooler. Basically, if you need something made cold, refrigerant is usually involved in some way.

But what is it? How does it work? Is it safe? Since refrigerant is usually “out of sight, out of mind,” these are questions most people do not  think of. But since we use refrigerant all the time, at home, at work, and in the car, it’s basic information that you should probably know.

Below is most everything that the layman needs to know about refrigerant.



What is refrigerant?

A refrigerant is basically a liquid or a gas with a very low boiling point. Where water normally boils at 212 degrees Fahrenheit (and freezes at 32 degrees), a refrigerant like R-134a boils at 15 degrees below zero (and freezes at -154).

There are a lot of substances that fit that definition and can be used as refrigerants. A number of them are used as refrigerants in different types of cooling systems today.

How does refrigerant make things cold?

If you want to make anything cooler, you need to remove heat from it. That’s because “cold” isn’t really a thing; coldness is just a lack of heat.

The refrigerant in an A/C system cools the air by absorbing heat. Any time something boils, it is absorbing heat; a pot of water only boils when it absorbs heat from a hot stove. Since the boiling point of refrigerant is so low, the warm air in your car is like a hot stove in comparison. The refrigerant boils or evaporates into a gas, absorbing heat from its surroundings and leaving the air cooler.

That’s actually the easy part of an A/C system; the hard part is turning the refrigerant back into a liquid so it can repeat the cycle. This is accomplished by pressurizing the refrigerant (with a compressor). Raising the pressure raises the boiling point; under high pressures, the refrigerant behaves a bit more like water. That means it’s a liquid even on a 100-degree summer day.. When the liquid re-enters the cooling part of the A/C system, that pressure is reduced, allowing it to boil and begin the process of cooling the air again.

For more details on the parts of an A/C system, check out How a Car A/C Works.

Can any refrigerant be used in any A/C system?

No. A/C systems are designed to work with a particular kind of refrigerant, and they may not work at all if you try to use a different type. Some air conditioners can be converted to work with a new refrigerant, though, such as when you convert an old R-12 system to R-134a.

What kind of refrigerant is used in car air conditioners?

Before 1994, R-12 was the most common refrigerant used in automobiles. Since 1994, almost all cars use R-134a, including many old R-12 systems that have been converted. There is a new refrigerant called R-1234yf (or HFO-1234yf) that is beginning to be used in some brand-new cars, mostly in Europe.

What do the R-numbers mean?

Most refrigerants have rather awkward chemical names, such as “dichlorodifluoromethane” or “1,1,1,2-Tetrafluoroethane.” To simplify the names, a numbering system was developed: R-12, R-22, R-134a, R-1234yf, etc. The “R” just stands for “refrigerant,” while the numbers and letters identify which refrigerant you’re talking about.

Do refrigerants damage the ozone layer?

Some old refrigerants, like R-12, were widely used until it was discovered that they could potentially react with ozone in the atmosphere. Because of this, they were phased out and replaced by safer refrigerants which do not damage ozone. That’s why cars built after 1994 use R-134a instead of R-12: R-134a does not damage the ozone layer.

Isn’t it illegal to handle refrigerant yourself?

Not at all. It’s true that some older refrigerants have been removed from the market, and can only be bought or used if you have the proper permits and licenses. But the R-134a used in cars today (and in cans of A/C Pro) is considered safe and simple enough for anyone to use, and can be bought off the shelf at most any auto parts store or in the auto department of major retailers.

If you have any other questions, feel free to check out our FAQ section or simply ask the pro. We’re happy to help.