How cheap are you?

[Ronstang]

Originally posted by: aeroguy

Originally posted by: Vic

Originally posted by: aeroguy
If you're going down the highway at 60 or 70 mph you don't save any gas by rolling down the window. In fact, some studies have shown you actually use more gas with the windows down than using the A/C because of the aerodynamics.

Edit: and don't forget that drag increases with the square of velocity, so the faster you go, the higher the drag, and you have higher fuel consumption.

Myth.

Prove it. Saw a mythbusters episode on it. When they tested with computers the A/C option was better (11.7 vs. 11.2 mpg I think). When they drove around the track with 5 gallons in the tank, the windows down option was better, but they used two different vehicles unlike the fist test.

And drag increasing with the square of velocity is definately not a myth.

You are a perfect example of someone whose entire knowledge base was learned out of a book in school. You can apply all the equations to this situation you want but you won't be able to show one damn thing. The truth is that at normal highway speeds the AC will cost you more gasoline then having the windows down, just as it will in the city. I have been keeping track of every tank of gas from every car I have ever owned for the last 26 years. I always check the mileage at fillup time. I do this to make sure the vehicle is always running it's best. The one thing I can emphatically say is that you get better mileage with the windows down than you do with the AC on because it has been proven to me time and time again when I calculate my mileage. Every single car exhiited this behavior so you cannot use the aerodynamics since a lot of my cars have been and still are classics. My 93 Taurus SHO used to get ~29 mpg on the highway at 70 mph with the windows down, and ~27 mpg at 70 mph with the AC on. This proved itself to be true over and over and over as I drove this car 220K miles checking my mileage at every fillup with my overall average mileage per tank of ~23 mpg.. You do the math....my sample population on just this car is too big to call an anomoly. You are SIMPLY WRONG. Mythbusters first test was incorrect because they assumed the computer data to be correct and their testing model was wrong, I realized this as I was watching it and hoped they would not just report the AC on is more efficient, call it a day and be WRONG.....but real world testing proved the truth.

 

[Vic]

Thanks, Ronstang. I was going to say that my own proof comes from my own very extensive mileage records (although, admittedly, not as extensive as yours) and experience. Anyone who is in tune with their vehicle can feel how it is running. With windows up or down, I feel virtually no change in throttle position needed to hold a given highway speed. But turn on the AC with windows up, and I instantly feel the sluggishness of the car and the need for more throttle to hold a given speed, and that means more gas will be consumed per mile. 2+2=4, always.

It sometimes amazes me how people will believe only what they read (or are told) even when that belief is in direct contradiction to their own personally experienced reality.

 

[hzl eyed grl]

There's NO way I'm going without A/C. NO WAY!

 

[aeroguy]

Originally posted by: Ronstang

Originally posted by: aeroguy

Originally posted by: Vic

Originally posted by: aeroguy
If you're going down the highway at 60 or 70 mph you don't save any gas by rolling down the window. In fact, some studies have shown you actually use more gas with the windows down than using the A/C because of the aerodynamics.

Edit: and don't forget that drag increases with the square of velocity, so the faster you go, the higher the drag, and you have higher fuel consumption.

Myth.

Prove it. Saw a mythbusters episode on it. When they tested with computers the A/C option was better (11.7 vs. 11.2 mpg I think). When they drove around the track with 5 gallons in the tank, the windows down option was better, but they used two different vehicles unlike the fist test.

And drag increasing with the square of velocity is definately not a myth.

You are a perfect example of someone whose entire knowledge base was learned out of a book in school. You can apply all the equations to this situation you want but you won't be able to show one damn thing. The truth is that at normal highway speeds the AC will cost you more gasoline then having the windows down, just as it will in the city. I have been keeping track of every tank of gas from every car I have ever owned for the last 26 years. I always check the mileage at fillup time. I do this to make sure the vehicle is always running it's best. The one thing I can emphatically say is that you get better mileage with the windows down than you do with the AC on because it has been proven to me time and time again when I calculate my mileage. Every single car exhiited this behavior so you cannot use the aerodynamics since a lot of my cars have been and still are classics. My 93 Taurus SHO used to get ~29 mpg on the highway at 70 mph with the windows down, and ~27 mpg at 70 mph with the AC on. This proved itself to be true over and over and over as I drove this car 220K miles checking my mileage at every fillup with my overall average mileage per tank of ~23 mpg.. You do the math....my sample population on just this car is too big to call an anomoly. You are SIMPLY WRONG. Mythbusters first test was incorrect because they assumed the computer data to be correct and their testing model was wrong, I realized this as I was watching it and hoped they would not just report the AC on is more efficient, call it a day and be WRONG.....but real world testing proved the truth.

The second test was no better than the first test because they used two diffent vehicles on the second test. You and I both know they should have used the same vehicle. As far as the computer model being inaccurate, that's possible, but how can you say that their computer model was totally wrong without having proof? Your "study" doesn't prove anything to me either. You're telling me that you sometimes drive EVERY mile with the windows up between fillups and sometimes EVERY mile with the windows down? And you drive the EXACT same way every time? I just can't take your word for it, sorry. Show me a controlled scientific study that proves your point, at interstate speeds (70 mph, no braking or accellerating), then I will cede your point.

 

[aeroguy]

Here's a study from SAE. I haven't read it yet so hopefully I'm not too

 

[Vic]

The issue here is that there will never be a conclusive test. Why? Because a torquey large displacement engine will hardly even notice the AC is on while a smaller displacement engine will think you just hitched up a trailer. That's how it is.
Want a real test? How up an intake manifold vacuum gauge (aka "boost gauge" in turbo-equipped cars) in your car and pay attention to the difference in manifold pressure with windows up/down, AC on/off. The more negative the vacuum pressure in the intake manifold, the better the fuel economy -- this is proven science.
I happen to have one of those gauges in my car, so I know for fact which is more efficient. But then I also have a small displacement turbocharged engine in my car, so any time I have to go into boost (positive intake manifold pressure), I'm eating gas. Fuel economy is easy in such a car, just stay off the boost. Well, easier said than done

 

[Vic]

Originally posted by: aeroguy
Here's a study from SAE. I haven't read it yet so hopefully I'm not too

It said that fuel consumption (measured in gal/mile for that test, not the usual miles/gal) was worse with the AC on than with windows down, even at highway speeds (pages 14-15). The key part of the study was where it said, "If the customers turn the AC off to save fuel, and rolls the windows down, fuel consumption may not improve as much as customer expects." (page 2)
It's also well to note that both vehicles were full-size with large displacement engines (4.6L V8 in the sedan and 8.1L :Q V8 in the SUV). (page 11)

 

[aeroguy]

Touche to vic and ronstang.

It looks like windows > A/C, but only slightly in a sedan (unfortunately they don't show the y-axis so we can't see how much). Page 15 of the above link proved it to me.

I hate being wrong, but will still use the A/C

 

[Ronstang]

Originally posted by: aeroguy

Originally posted by: Ronstang

Originally posted by: aeroguy

Originally posted by: Vic

Originally posted by: aeroguy
If you're going down the highway at 60 or 70 mph you don't save any gas by rolling down the window. In fact, some studies have shown you actually use more gas with the windows down than using the A/C because of the aerodynamics.

Edit: and don't forget that drag increases with the square of velocity, so the faster you go, the higher the drag, and you have higher fuel consumption.

Myth.

Prove it. Saw a mythbusters episode on it. When they tested with computers the A/C option was better (11.7 vs. 11.2 mpg I think). When they drove around the track with 5 gallons in the tank, the windows down option was better, but they used two different vehicles unlike the fist test.

And drag increasing with the square of velocity is definately not a myth.

You are a perfect example of someone whose entire knowledge base was learned out of a book in school. You can apply all the equations to this situation you want but you won't be able to show one damn thing. The truth is that at normal highway speeds the AC will cost you more gasoline then having the windows down, just as it will in the city. I have been keeping track of every tank of gas from every car I have ever owned for the last 26 years. I always check the mileage at fillup time. I do this to make sure the vehicle is always running it's best. The one thing I can emphatically say is that you get better mileage with the windows down than you do with the AC on because it has been proven to me time and time again when I calculate my mileage. Every single car exhiited this behavior so you cannot use the aerodynamics since a lot of my cars have been and still are classics. My 93 Taurus SHO used to get ~29 mpg on the highway at 70 mph with the windows down, and ~27 mpg at 70 mph with the AC on. This proved itself to be true over and over and over as I drove this car 220K miles checking my mileage at every fillup with my overall average mileage per tank of ~23 mpg.. You do the math....my sample population on just this car is too big to call an anomoly. You are SIMPLY WRONG. Mythbusters first test was incorrect because they assumed the computer data to be correct and their testing model was wrong, I realized this as I was watching it and hoped they would not just report the AC on is more efficient, call it a day and be WRONG.....but real world testing proved the truth.

The second test was no better than the first test because they used two diffent vehicles on the second test. You and I both know they should have used the same vehicle. As far as the computer model being inaccurate, that's possible, but how can you say that their computer model was totally wrong without having proof? Your "study" doesn't prove anything to me either. You're telling me that you sometimes drive EVERY mile with the windows up between fillups and sometimes EVERY mile with the windows down? And you drive the EXACT same way every time? I just can't take your word for it, sorry. Show me a controlled scientific study that proves your point, at interstate speeds (70 mph, no braking or accellerating), then I will cede your point.

I have been testing this theory for 26 years. I don't care what you WANT to believe. I have driven full tanks on trips with the AC...27 mpg...same trip in the evening coming back 29 mpg. This has repeated itself over and over again, I know I am driving the same way....I am on the fricken highway with the speed control on!! I wouldn't give you info if I wasn't sure it was true. Everytime I used the AC on a long trip with only highway miles the mileage was ~27 mpg and everytime I used a whole tank on the highway with the windows down it was ~29 mpg....EVERY TIME. I don't care what you think. I KNOW WHAT THE TRUTH IS. It has worked the same for every vehicle I have owned or driven for any length of time over the last 26 years. I only use the AC when I absolutely have to so I know ho using it affects my mileage.

 

[aeroguy]

Originally posted by: Ronstang

Originally posted by: aeroguy

Originally posted by: Ronstang

Originally posted by: aeroguy

Originally posted by: Vic

Originally posted by: aeroguy
If you're going down the highway at 60 or 70 mph you don't save any gas by rolling down the window. In fact, some studies have shown you actually use more gas with the windows down than using the A/C because of the aerodynamics.

Edit: and don't forget that drag increases with the square of velocity, so the faster you go, the higher the drag, and you have higher fuel consumption.

Myth.

Prove it. Saw a mythbusters episode on it. When they tested with computers the A/C option was better (11.7 vs. 11.2 mpg I think). When they drove around the track with 5 gallons in the tank, the windows down option was better, but they used two different vehicles unlike the fist test.

And drag increasing with the square of velocity is definately not a myth.

You are a perfect example of someone whose entire knowledge base was learned out of a book in school. You can apply all the equations to this situation you want but you won't be able to show one damn thing. The truth is that at normal highway speeds the AC will cost you more gasoline then having the windows down, just as it will in the city. I have been keeping track of every tank of gas from every car I have ever owned for the last 26 years. I always check the mileage at fillup time. I do this to make sure the vehicle is always running it's best. The one thing I can emphatically say is that you get better mileage with the windows down than you do with the AC on because it has been proven to me time and time again when I calculate my mileage. Every single car exhiited this behavior so you cannot use the aerodynamics since a lot of my cars have been and still are classics. My 93 Taurus SHO used to get ~29 mpg on the highway at 70 mph with the windows down, and ~27 mpg at 70 mph with the AC on. This proved itself to be true over and over and over as I drove this car 220K miles checking my mileage at every fillup with my overall average mileage per tank of ~23 mpg.. You do the math....my sample population on just this car is too big to call an anomoly. You are SIMPLY WRONG. Mythbusters first test was incorrect because they assumed the computer data to be correct and their testing model was wrong, I realized this as I was watching it and hoped they would not just report the AC on is more efficient, call it a day and be WRONG.....but real world testing proved the truth.

The second test was no better than the first test because they used two diffent vehicles on the second test. You and I both know they should have used the same vehicle. As far as the computer model being inaccurate, that's possible, but how can you say that their computer model was totally wrong without having proof? Your "study" doesn't prove anything to me either. You're telling me that you sometimes drive EVERY mile with the windows up between fillups and sometimes EVERY mile with the windows down? And you drive the EXACT same way every time? I just can't take your word for it, sorry. Show me a controlled scientific study that proves your point, at interstate speeds (70 mph, no braking or accellerating), then I will cede your point.

I have been testing this theory for 26 years. I don't care what you WANT to believe. I have driven full tanks on trips with the AC...27 mpg...same trip in the evening coming back 29 mpg. This has repeated itself over and over again, I know I am driving the same way....I am on the fricken highway with the speed control on!! I wouldn't give you info if I wasn't sure it was true. Everytime I used the AC on a long trip with only highway miles the mileage was ~27 mpg and everytime I used a whole tank on the highway with the windows down it was ~29 mpg....EVERY TIME. I don't care what you think. I KNOW WHAT THE TRUTH IS. It has worked the same for every vehicle I have owned or driven for any length of time over the last 26 years. I only use the AC when I absolutely have to so I know ho using it affects my mileage.

Chill out dude. It wasn't that hard to find something that you and I could both read and be convinced by. Now wasn't that easier?

 

[imported_malcontent]

I run the AC nearly all year here in Tx. There is no way I am driving around in 90+ heat without AC.

 

[lokiju]

My daily driver is a work provided van with a gas card so you bet your ass that AC is on all the time, but even if it was my own ride and my own $$ for the gas I'd still have the AC on when its 80F+ out.


I drive my Tahoe on the weekends and now that its summer I have the AC on, if I'm on the highway though I'll put down the windows down even with the ac on just to get the fresh air.

 

[DaWhim]

my AC just doesn't work well during the day time when it is really hot.

 

[Ronstang]

Originally posted by: aeroguy
Touche to vic and ronstang.

It looks like windows > A/C, but only slightly in a sedan (unfortunately they don't show the y-axis so we can't see how much). Page 15 of the above link proved it to me.

I hate being wrong, but will still use the A/C

I didn't see this post. But then again I didn't need to since I have been testing and confirming the results for 26 years.

 

[Siva]

Mannnnnnnnnn I'm so cheap when its just me in the car. Unless its 100+ and I'm in traffic the A/C stays off because I'm driving like 600 miles every week and gas is EXPENSIVE. If someone else is in the car (ie not during my regular commute) then I will turn on the air if it is reasonably hot, I don't mind for my friends at all.

 

[Excelsior]

Comfort comes first..but that isn't what one of my Jew friends thinks. She drove me and my friend back from college this past semester, in her Altima. This is in NC, so it is fairly warm. However, she thinks that she needs to keep the AC off most of the time to save gas. Then when we get there she asks me for $10 (this was only a 2 1/2hr drive) and refuses to actually drive me and my roommate to our homes even though mine was on the way, and she lives no further than 7-10 min from his.

What a fvcking jew.

 

[Kelemvor]

I haven't used the A/C in my car in years. If I was going on a long trip I would... But I normally just go to work and back and take less than 10-15 minute drives.

 

[lobadobadingdong]

I live in Texas, when the inside car temp reaches upwards of 185F you betcha I use the AC, with the windows rolled down while driving 65mph my thermometer still hits 110F when its only 95F outside....and we haven't even hit the 100's yet this year.

 

[IHateMyJob2004]

As Imentioned in the other thread:

windows down + 30 years = deaf in left ear

 

[monk3y]

Nah, I always use the AC.

 

[Ronstang]

Originally posted by: IHateMyJob2004
As Imentioned in the other thread:

windows down + 30 years = deaf in left ear

That is utter crap. Try again.

 

[Anubis]

always use the ac, always also have to yell at my dad who puts teh windows down when it 110 out

 

[Squisher]

I don't particularly like A/C, but if I have someone in the car I'd turn it on in a second.

 

[PHiuR]

i will use A/C but i prefer windows even when im going 80MPH!

 

[aeroguy]

Originally posted by: Ronstang

Originally posted by: aeroguy
Touche to vic and ronstang.

It looks like windows > A/C, but only slightly in a sedan (unfortunately they don't show the y-axis so we can't see how much). Page 15 of the above link proved it to me.

I hate being wrong, but will still use the A/C

I didn't see this post. But then again I didn't need to since I have been testing and confirming the results for 26 years.

Do you think it is worth the money saved to not be as comfortable?

Assuming you drive half your 12,000 miles when the ambient temperature is above your comfort level and half below:

6000 miles at 29 mpg = 207 gallons x $2 per gallon = $414
6000 miles at 27 mpg = 222 gallons x $2 per gallon = $444

So you save $30 per year with the windows open vs. A/C on. Even if you drive 12,000 miles per year in the heat you only save $60.