Glad You Asked

By Journal Times staff

Saturday, September 8, 2007 8:52 PM CDT

We had a question come in a few times in recent weeks, and it surprised me. I guess it’s a testament to our recent warm weather. We dealt with the issue earlier this summer; we’ll look at it again.

Is it true you use more gasoline when you use the air conditioner when you’re driving? I was told you didn’t.

You’d think this question would be easy. We found a few schools of thought on this issue. One school says you don’t use more gas when running the A/C because your vehicle is more aerodynamic with the windows rolled up (presuming, of course, the choice is between air conditioning or rolling down your windows to cool off your car). Another school says that A/C requires power, and the only way you get more power in your car is by running your engine harder and burning more gas.

We suspect there’s a middle ground between these answers. At high speeds, like on the Interstate, it makes sense that aerodynamics would be important for a vehicle’s fuel-efficiency. At lower speeds, it doesn’t seem so important, so it could be more fuel-efficient to roll down the windows.

For an expert’s opinion, we turned to the good folks at the TV show “MythBusters” for help. In November 2004, they did a show on this very question and got some confounding results. A computer model suggested that the drag from rolling down car windows was greater than the power drain from using A/C. But when the show’s hosts put the theory to the test on a race track, a sport utility vehicle running at 45 mph with A/C ran out of gas before an SUV running at the same speed with its windows down.

We suspect the key is speed. If you’re speeding along a highway, pop on the A/C for the best gas mileage (and save your hair from blowing around). If you’re cruising around town, roll down the windows, save a little gas and wave hello to your neighbors.

Upcoming questions

Here are some questions we’re going to examine this week. Want to help us find answers? Then let us know if you know something.

Why is Horlick High School’s home field Hammes Field?

Do you know when Douglas Avenue will be repaved from 3 Mile Road south?

What is the technology that ensures that railroad crossing arms come down and prevent car/train accidents?

I was wondering if you could let me and other readers know the largest size trash cans you can put out for garbage collection. I was going to buy new ones about the size of 50 (gallons) and was told by someone the city will not pick them up.

Okay, how early is too early to put Christmas decorations up in the store? I was stunned to see Hobby Lobby has rows and rows of trees and ornaments, enough is enough! I thought Halloween was bad. Go take a look; it made me sick!

Does the DNR plan on getting rid of any other non-native species in the area after they get rid of mute swans?

I have a small microwave. Where can I dispose of it?

What is the rule about parking near someone’s driveway? How close can you be, or how much room do you need to leave?

What is going in the building immediately west of Farm & Fleet in Sturtevant?

I am on a very strict low-cholesterol diet. Where in town, if anywhere, do they sell nonfat yogurt or nonfat ice cream?

Why wasn’t there a book for the lighthouses, similar to the book printed for the dogs and cats?

Who is on the Landmark Preservation Commission?

What is Glad You Asked?

Glad You Asked seeks answers to your questions. Have a question? Send it to us at ask@journaltimes.com or call (262) 631-1758. Thanks!

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