When I was growing up in the 80s, we had a refrigerator that, by my estimates, must have been made in the 60s. Despite its age, it still kept our food as cold as we needed it. We also had a few window-mount air conditioners that could easily have been 20 years old, and they still blew air so cold an Eskimo would have felt at home. Their systems were obviously sealed completely.
But as any automobile owner knows, keep your car for more than 3-4 years and you’ll soon be paying for an air conditioner recharge. Everyone accepts this without question; car air conditioners slowly lose refrigerant, and that’s just the way it is.
Why? Why can’t GM or Honda build 'em like GE or Whirlpool?
Well, obviously, automobile air-conditioning systems lose refrigerant when they have leaks. So the question is why are they more prone to developing leaks than home refrigerators?
Two WAGs, both of which may be operative:
1.) Unlike your home 'frig, they move around and experience all kinds of motion stresses that your frig doesn’t, and,
2.) Your 'frig stays home inside, in an environment that doesn’t experience the extremes of heat, cold and humidity variation that is seen in the environment in which your automobile is operated.
The electric motor of the refrigerator or home A/C is inside the circuit, bathed in refrigerant. The car a/c compressor has a rotating shaft coming outside to a pulley which is moved by the engine. Making this seal effectively is much more difficult.
Cars are subject to temp extremes, and this impacts the flexability of rubber hoses,parts, seals and gaskets. All the temp changes, humidity changes and corrosion from pollution, road grime and salt that gets kicked up all take a toll on these parts. Vibration doesn’t help either.
The compressor, which pumps the refrigerant around, is necessarily mounted on the engine, so that it can be driven by a belt and pulley. The other components–evaporator, condenser, receiver-dryer, et cetera–are fastened to various places on the car’s body.
Since car engines vibrate, it is necessary to install them with soft rubber mounts. Have a friend move the transmission from Reverse to Drive and you can observe the engine flexing on its mounts. For this reason, rubber hoses are used for plumbing the compressor to the other bits—metal pipes would break instantly. They design the rubber hoses as best they can, but with all that motion, it’s probably hard to make them last forever.
The condenser, which looks like a skinny car radiator, is mounted in front of the regular radiator, right behind the grille. It sometimes gets hit by small rocks and such, which is unlikely to happen on your home unit.
Also, the temperature extremes are enormous–not only is the unit right next to a hot engine in summer, but the AC also runs in winter, when you turn on your windshield defroster.
These are all just educated guesses. I’ve only done a small amount of air conditioner repair, not enough to fully know what I’m talking about yet. I find it informative to visit the message boards at www.aircondition.com.
[“same on this side”] *sailor got it. The refrigeration unit in home refrigerators and freezers is in a sealed enclosure with no shafts in or out.
The refrigeration unit in an automobile, actually only the compressor, has a shaft coming out with a pulley for driving it from the engine. This shaft has a seal that can, and does, leak. I run my auto air conditionor for a short time about once a week in winter so this seal won’t have a chance to take a “set” from inactivity and thus leak.[/“same on this side”]
Not only that, but it’s not necessarily a given that your car AC will die within three or four years. I’ve only had one AC need to be recharged, and that was on a car rulling into eight years. My last car AC hadn’t been changed in six years, and I have a car sitting at home that still has a working AC after 34 years.