Summer has at last arrived. Good thing your air conditioning is working. One day soon, you’ll come out to the car on a 90-plus day and find that it’s a virtual oven in there. As soon as you slide into the driver’s seat, beads of sweat will appear on your brow. It’ll almost burn to touch the steering wheel. But, no problem; you’ll turn on the AC and, within minutes, nice cool air will pour out of the vents.

You may find yourself driving down the road thinking how nice the cold air feels in your face. And it is nice. You’ll drive along thinking how nice it is and telling yourself how soon you’ll feel nice and comfortable. You may say that to yourself again, and even again. At some point, you’re liable to have a discouraging thought spoil the moment: “Is it taking longer for the AC to cool the car?”

No, there’s a good chance that isn’t your imagination. Automotive air conditioning doesn’t often stop working all at once. It’s not a matter of it works or it doesn’t; rather, it’s a matter of how well it works. After a summer or two, there’s a good chance that it’s not going to work as well as it did before.

When the efficiency of your AC diminishes, you’ll still feel cool air coming from the vents, just maybe not as cool as before. And it may take longer for the conditioned air to reach its maximum cooling.

In reality, the AC doesn’t so much work by blowing cold air out of the vents; it works by pulling hot air out of the car and removing the heat before it returns the ‘conditioned’ air back into the vehicle. This is accomplished by having the hot air pass over a coil. Within the coil are tubes that have Freon running through them. The Freon is substantially colder than the hot air from the car.

As the hot air passes over the coil, and the tubes within, the heat is displaced from the air to the Freon. The air is now ready to return to the cabin without all that heat it previously contained.

Over time, the Freon may slowly escape from the system – not enough to cause an immediate problem but enough that it eventually leaves the system short on Freon. There are other potential problems with a car’s AC, such as compressor that doesn’t work properly or efficiently. But, most of the time, reduced efficiency of a car’s air conditioning system is related to the Freon.

A qualified auto repair technician will inspect the AC system’s hoses, seals, connections and other components for a leak. They’ll also inspect the compressor, clutch and drive belt. Finally, they’ll take temperature readings to determine the overall efficiency of the system.

If all the other checks were negative, they’ll check the Freon level in the system and add appropriate Freon as necessary. When they’re done, you’ll find that your AC system probably works as well today as it did when it was new. You’ll find that you cool off as quickly as you used to.