Aug

Mythbusters’ mistakes in AC vs windows down episode

Posted by admin Published in MPG, Green

Recently, I wrote an article on the debate; do you get better mileage with AC on and windows up or AC off and windows down? A comment in the spread said a Mythbusters episode found you could get better mileage with AC off and windows down. The way Mythbusters tackled the myth in that episode was just horrible. The myth was revisited in another episode, which I ordered and will review soon. So, what did they do?

They got an SUV and attached a sensor that estimates mileage by measuring air flow to the engine. They did 15 laps around a track, with a fixed speed of 45 MPH, measuring mileage as they went. They did 5 laps with the AC off and windows down. 5 laps with AC off and windows up. 5 laps with the AC on and windows up. No laps for AC on and windows down. Here are the results.

AC off, windows up = 11.7 MPG
AC off, windows down = 11.3 MPG
AC on, windows up = 11.7 MPG

So, according to these tests, AC use does not affect mileage. Windows down hurts mileage about 5 percent. The better option is turn on your AC. Rolling down your window makes little difference at all. Apparently unsatisfied, they tried a totally new tryout, measuring mileage differently and even changed the variable of speed. that is vital for the revisit which showed speed was very crucial. How they did moment analysis is after the jump.

They get two SUVs and emptied the gas tanks. next filled both tanks with precisely 5 gallons of gas. They both drive around the track, same loads, that duration at 55 MPH. One SUV has AC

off and windows down, while the other has AC on and windows up. The AC on and windows up SUV stopped first. The AC off and windows down SUV went a 15 percent greater distance.

So, whether you trust that analysis, AC burns 15 percent increasingly gas. Windows down is the way to go. They end by saying they did not really trust the first experiment considering it was just an estimate. The moment tryout was full proof and show the best option for saving fuel and keeping cool was windows down and AC off. Where to start with the mistakes? First, you don’t change your examining methods considering you don’t like the results.

It’s really the first rule of the scientific method. You have to attack the method of estimating mileage with air flow. You can’t just say, it did not do what I wanted, so it’s useless. What’s the point of an experiment whether you can do that? Didn’t they look into whether air flow could degree mileage before hand? They should do experiments or research on the how sensitive air flow measurement is in estimating mileage changes.

Changing the speed to 55 MPH in the moment analysis is just inexplicable. They had suitable problems going to a different way of measuring mileage and not doing ample experiments. In the middle of all of that, why throw in another variable? They really needed to do a lot increasingly trials and be a lot increasingly careful. I really don’t have much hope for their methods in the revisit. These are really basic mistakes.

[Source: Mythbusters]
Original post by Lascelles Linton