We’re into the peak of summer travel season, which of course also means trying to stay cool in the car.
But with gas prices rising toward $4 a gallon again, is it wise to cool the car with air conditioning? Popular Mechanics provided tips for ways to save on gas this summer.
Some were simple, such as coasting to a stop instead of slamming on the brakes. Keeping your car moving saves gas by not having to start from a dead stop. Also, slow down on the highway – fuel use jumps quickly as you accelerate above 60 mph. It might not be realistic to expect drivers to go 55 mph, but you should at least try to avoid going 80 mph.
Some of the rules surprised me, such as not accelerating too slowly. It seems to make sense to crawl up to cruising speed, but the study showed it reduces the time you are at your peak cruising speed, when fuel efficiency is at its highest. While all vehicles are different, the study found taking 15 seconds to accelerate to 50 mph is more efficient than taking 30 seconds to reach that speed.
Finally, it tried to answer the never-ending question of air conditioning versus open windows. Like me, the study decided just sweating in your car wasn’t a viable option.
At 55 mph, the test vehicle got 24 mpg with the air conditioner running. When it was turned off, efficiency jumped to 28 mpg, but that dropped by 1 mpg for each window opened, essentially making it a wash at that speed. Higher speeds, however, showed a bigger drain on gas mileage with the windows open than with the air conditioning.
Debate settled? Not quite. While Popular Mechanics put the cutoff for windows versus air conditioning at 60 mph, other studies have found conflicting results. Discovery Channel’s series “MythBusters” found air conditioning should be avoided regardless of the speed, and ConsumerReports.org found the same thing when testing a Honda Accord.
“The effect of opening the windows at 65 mph was not measurable,” according to ConsumerReports.org.
This conflicting information likely is based on the fact all vehicle models are different. Drivers also use their air conditioner differently – full blast uses more fuel, obviously. I’ll continue to drive comfortably by using the air when it’s hot and rolling down the windows when it’s cooler.