Is it true that keeping your windows down takes up just as much gas as the A/C?

Question

I hear often that the resistance of the wind takes up just as much gas as the A/C. I've been saying I'll just start putting the windows down in the morning, but in the afternoon I have to have the A/C. I live in Florida and the temp is almost a hundred if not more in August.

Answer 1

no. its not

Answer 2

I will bet you thought this question had a simple answer! This forum has discussed this issue many times lately. This question actually asks: at what vehicle speed or temperature does the extra aerodynamic drag caused by rolled down windows sap more power than running the A/C compressor or vice versa?

In July of 2004 four GM engineers presented a paper at a Society of Automotive Engineers conference which addressed these questions in a scientific manner. Here are some of the findings (at much risk of oversimplification):
1. Below about 60-65F (air temperature) at between 31 and 68mph, using the A/C is more economical than rolled down windows.
2. After about 68F, A/C fuel consumption is always higher regardless of vehicle speed.
3. The most economical driving method is A/C off, windows up.
4. Notwithstanding the above, individual results are dependent upon many other factors.

Based on this and other already mentioned references, the answer is generally NO, especially in Florida in the summer.

Answer 3

No it is not true, however,
during peak heat moments, like now, it is not fiscally wise.
The HVAC or AC has to recover or produce the desired temperature so it is not economical nor is it ecological to make the unit work twice as hard to reach the desired setting.
Here is a ok article on that:
Potential for Natural Ventilation and Operable Windows

In some parts of the country, where temperature and humidity levels permit, natural ventilation through operable windows can be an effective and energy-efficient way to supplement HVAC systems to provide outside air ventilation, cooling, and thermal comfort when conditions permit (e.g., temperature, humidity, outdoor air pollution levels, precipitation). Windows that open and close can enhance occupants' sense of well-being and feeling of control over their environment. They can also provide supplemental exhaust ventilation during renovation activities that may introduce pollutants into the space.

However, sealed buildings with appropriately designed and operated HVAC systems can often provide better indoor air quality than a building with operable windows. Uncontrolled ventilation with outdoor air can allow outdoor air contaminants to bypass filters, potentially disrupt the balance of the mechanical ventilation equipment, and permit the introduction of excess moisture if access is not controlled.

Strategies using natural ventilation include wind driven cross-ventilation and stack ventilation that employs the difference in air densities to provide air movement across a space. Both types of natural ventilation require careful engineering to ensure convective flows. The proper sizing and placement of openings is critical and the flow of air from entry to exit must not be obstructed (e.g., by closed perimeter rooms).

* Designers should consider the use of natural ventilation and operable windows to supplement mechanical ventilation. Consider outdoor sources of pollutants (including building exhausts and vehicle traffic) and noise when determining if and where to provide operable windows.

* If operable windows will be used to supplement the HVAC system, ensure that:

o openings for outdoor air are located between 3-6 feet from the floor (head height);
o the windows are adjustable and can close tightly and securely;
o the windows are placed to take maximum advantage of wind direction, with openings on opposite sides of the building to maximize cross-ventilation.

http://www.epa.gov/iaq/schooldesign/hvac.html#Potential%20for%20Natural%20Ventilation%20and%20Operable%20Windows
http://www.epa.gov/iaq/largebldgs/baqtoc.html
Keep thinking!
http://www.trustmymechanic.com/ac_troubleshooting.htm

Answer 4

At freeway speeds, and depending on the air-frame of the car, it is generally more efficient to use the A/C than to have the windows open.

Also, it is safer to have the windows rolled up -- on many cars the low-frequency buffeting caused by open windows can cause driver fatigue, and even at freeway speeds, bees and hornets have been known to make it past the car's pressure wave (i.e. "wake") and fly into open windows, creating a distraction for some drivers.

Answer 5

either way is not really enough to see the differants if you got air use it.. and yes its about the same only a mile or too differant i live in vegas where above 100's are daily your not wasting money by using it but it does put strain on the motor sometimes if the cars are not moving dont woory just use it and be happy you cool

Answer 6

actually if you had watched myth busters you would know the answer...2 identical ford explorers..1/2 mile track...truck with air on went 10 laps less than one with windows down a/c off...

Answer 7

either way is just about the same... windows down creates drag.... a/c on creates strain on engine

Answer 8

YO--you do not have any thing to prove just enjoy driving-- stay off the cell phone. -- Be safe---OK

Answer 9

SAME QUESTION AGAIN.............SAME ANSWER AGAIN

IT WAS PROVEN THAT YOU GET BETTER GAS MILEAGE WITH YOUR WINDOWS DOWN AND YOUR A/C OFF.

Answer 10

i do believe it is true. there is a show called myth busters and they actually did that experiment. you should check it out.

Answer 11

what mc.fatty pants?...scared the "ricans" will rob you?...