Car Air Conditioner Myths Busted: Is Your AC Killing Your Car?

Anyone who’s ever driven on a hot day with no air conditioning can attest to how uncomfortable that can be. Thankfully, AC is ubiquitous in cars, but despite its widespread use, some not-so-true notions about this must-have car feature persist. So what are some air conditioning myths? Keep reading to find out. 

AC Robs Horsepower

While there’s no doubt that AC does rob some horsepower, there is no one answer as to how much. The amount of power it draws depends on how old your car is, the condition of the AC system and engine, and the vehicle make and model, among other things. Not only are there many variables, but how they affect vehicle power on the road can also vary significantly.

In most cases, the change in power is difficult to detect. Some people with older cars do notice a drop in horsepower when they’re using AC on the road, but most late-model vehicle owners probably won’t notice much of a difference. And even if you do, for most drivers, the change isn’t enough to cause any significant problems on the road. 

AC Will Wear out Your Engine Faster

Some people try to limit their AC use due to a false belief that running the air conditioning will wear out their engine more quickly. To unpack this myth, it’s essential to talk about service life, which is the length of time an engine will perform optimally before needing replacement. Engine life can vary significantly, with some engines lasting 200,000 miles and others lasting up to 500,000. 

The simple truth is that placing a load—any load—on an engine reduces its working life over time. Things like power steering pumps, superchargers, alternators, and air conditioning compressors all constitute extra loads that force the engine to work harder. 

However, it’s vital to keep in mind that engines are supposed to provide a decent service life. Engineers consider these extra loads when designing cars, which means that something like AC use has already been factored into your engine’s service life. 

So does AC technically contribute to the eventual end of your engine’s life? Sure, but it’s one of many other loads doing so. The bottom line? Turning off your AC won’t make a considerable difference in helping your engine stand the test of time, so don’t let this myth stop you from using it.  

AC Is Bad for the Environment

You’ve probably heard of Freon, a common component in older air conditioners that was found to be detrimental to the ozone layer. Before 1992, all car air conditioners were manufactured with Freon. But when concerns about this component became known, lawmakers passed the Clean Air Act, which obligated manufacturers to use a refrigerant that’s safer for the ozone. 

While car air conditioning has come a long way, there are some environmental concerns to be aware of. Mostly, leaking AC units can be extremely damaging to the environment, which is why proper maintenance is essential. Routine tune-ups can help you identify and correct any air conditioning issues that could be having an environmental impact. 

You Shouldn’t Start the Car with AC On

This myth is quite pervasive, and the reason it persists today is that it was true of older cars. In older models, it took the engine a while to reach full efficiency after starting it, and it was hard for them to handle the significant power load of an AC compressor. If you kept starting an older car with the AC on (along with other accessories), its engine lifespan could eventually be shortened. 

Things are different nowadays. When the starter engages on new cars, most power-hungry accessories automatically switch off. So if you’re wondering “Can you start a car with the AC on?” the answer is yes—as long as your car is a 2007 model or later. 

Running AC Adversely Affects Gas Mileage

Like all machines, AC needs power to run. It gets power from your car’s engine, which runs on gas. Several factors influence how much power your AC takes from the engine, including outside weather conditions (the hotter it is outside, the greater the demand), the age of your car (newer cars are more efficient), and engine size, make, and model.

So does running the AC get bad gas mileage? The added demands it places on your engine do result in a slight dip, so there is truth to this statement. The good news is that, in most cases, the dip is comparatively small. You can also make small changes (such as driving slower and not placing objects on your roof when you drive) to improve fuel economy.  

AC Overheat Your Car

A properly functioning AC unit should not overheat your vehicle. However, this myth has a bit of truth to it in that other issues may cause overheating when coupled with AC use. These include: 

  • Problems with the radiator
  • A faulty fan
  • Compressor overload
  • A cooling system failure 

A mechanic can help determine which one of these problems is causing your car to overheat. A faulty AC unit may also be to blame. 

AC Makes You Drive Slower

The myth that AC makes you slower rings true for older, less powerful vehicles. But when we talk about new cars, there is only some truth to AC slowing you down. How much depends on what kind of car you’re driving and how you’re driving.

If you have a new, powerful car, it’s pretty impossible to tell the difference. More standard, family-friendly cars do experience a bit more of a slow-down, but for most people, the difference is negligible. You Should Turn off AC On Hills.

Plenty of people think that running the air conditioning while driving up a hill (especially long grades) will put too much stress on the engine. This myth was true of older cars, but today’s vehicles are built to function well in most conditions. So if you’re driving up an unending grade in summer, you can rest assured that AC use won’t cause adverse effects.

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