Car Air Conditioning Myths

With the hot weather rolling in, we get quite a few questions surrounding air conditioners here at Searles.  Air conditioning is a precious summer commodity, as anyone who has done a hot summer drive without AC will tell you.  Even in the cooler parts of Canada, it’s rare to find a vehicle without this feature.  Still this old invention’s popularity hasn’t stopped some very interesting strategies from popping up around AC, fuel efficiency and engines.

Here at Searles, we take a look at some of the myths surrounding AC and put them on ice!

Air Conditioning vs Windows Down

This one is a popular one, thanks to an episode of Myth Busters.  The show put two SUVs to the test – one with windows closed, and AC off, and the other with no air conditioning and windows open. Both vehicles were given 5 gallons in gas and driven around a track until they hit empty. In the end, the SUV with open windows outlasted its air conditioned companion, getting an extra 15% in mileage.

So tape over the AC button and keep the windows down all summer long, right? Well, unfortunately, things aren’t that simple.  The show only tested the vehicles traveling at one speed – 55 mph (88.5 km/h).  As speed increases, so does wind drag – and vehicles traveling on highways can see a dip of up to 20% once they reach highway speeds.

Instead, experts advise using a mix of the two strategies.  Keeping windows down will get better mileage for driving around town, but once you hit the highways, AC is the way to go.

Of course, you could play it safe for fuel efficiency and keep the windows up and AC off all summer, but your passengers may have some opinions on that.  (Why not check out our post on How to Get Better Gas Mileage instead?)

Don’t Start Your Engine with the AC On

This bit of advice applies to older cars.  Engines that have just been started are not very efficient, and on older carburetor models, the AC compressor can present a huge power load on start up. Repeatedly starting a vehicle with all the bells and & whistles on will eventually shorten the life of your engine.

Since 2007, however, most accessories are designed to shut off automatically when the starter is engaged.  While turning off the AC on a parked vehicle doesn’t hurt, it’s no longer necessary for newer cars.

Turn off the AC on Hills

It’s a commonly held belief that using AC while on a hill will make the engine work harder. As a result, many drivers reach for the air conditioner on a steep summer climb – much to the horror of their passengers.

While the air conditioners of yesteryear may have made cars prone to overheat, the cooling systems of modern vehicles are designed to work in all but the most extreme conditions. Today’s vehicles will automatically divert power to the engine as needed, meaning you can make those long drives up the Malahat in comfort.

Still concerned about engine wear and tear on those long climbs? Save that switch flipping for the radio, and lighten up on the gas pedal inseated! Slowing down remains the most efficient way to take the heat off of your motor.

If your car is overheating with the AC turned on, a blocked radiator or failing AC compressor may be to blame. Fortunately, Searles specializes in auto air conditioning repair, so be sure to book an appointment with one of our mechanics if you see that temperature gauge climbing!

Planning a road trip this summer? Trust Searles for all your Air Conditioning and Vehicle needs. Check out our latest Summer Maintenance Special. Get an oil, lube and filter change, plus a comprehensive visual inspection and tire rotation for only $99.95. (Plus enter to win a Roomba – the perfect way to keep the house clean while you’re out driving!)

Learn More

• How to Get Better Gas Mileage
• 3 Cool Things You Need to Know About Auto Air Conditioning (and One You Don’t)
• Our Guide to 3 Amazing BC Summer Road Trips