Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (2022)

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by Cobus F. Potgieter /

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Is the cost of using your car AC worth it when you could simply roll down your windows for free?

Read in this article:

  • The Fuel-Use Debate - Car AC or Windows Down?
  • Using Air-Conditioning
  • Pros and Cons
  • Rolling Your Car Windows Down
  • Pros and Cons
  • Tips on How to Cool Down Your Car’s Interior Quickly
  • How Much Does the AC Affect Gas Mileage?
  • Conclusion
  • FAQs

The Fuel-Use Debate - Car AC or Windows Down?

There is a school of thought that claims your car AC is a huge drain on your car engine and that it has a noticeable effect on your fuel usage. Another group claims that car air-conditioning is actually very efficient and that the drag caused by open windows is a larger detriment, especially on the highway. So, how much does the AC affect gas mileage as opposed to open windows, and what factors do you actually have to consider when making the calculations?

Using Air-Conditioning

As is to be expected, there are documented advantages and drawbacks to either choice. To be able to weigh the two properly, you need to know the pros and cons of using air-conditioning or climate control.

(Video) Air Conditioning vs. Windows Down - Best Gas Mileage

Pros and Cons

  • Convenience: A simple press of a button is all it takes to cool down the interior, even on a sweltering day when you can feel the burn of the sun.
  • Cleaner air: Almost all modern cars sold in the US have cabin filters that remove dust and pollen from the incoming air. You're breathing cleaner air with the AC on and the windows closed.
  • Faster demisting: Blending in air-conditioned air when your car's demisting function is used speeds up the process because the AC dries out the air and removes moisture from the glass faster.
  • Increased fuel consumption: The air-conditioner compressor runs off the engine with a belt and steals horsepower, which, in turn, uses extra fuel. In an SUV with a powerful AC, such as a Land Rover Defender, the fuel drain is significant.
  • Drains engine power: The air-conditioner can drain a noticeable amount of engine power, depending on the type of car. Small hatchback cars with weak engines suffer most. Sports cars with powerful engines simply shrug off the load.
  • Engine temperature: The AC places extra demands on an engine, so make sure your car's cooling system is in good condition.
  • Can cause irritation: Because of its drying effect, an air-conditioner can irritate some people and dry out their eyes.

Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (1) unsplash.com

Rolling Your Car Windows Down

Then there's the alternative. Sometimes, you don't need a high-tech solution to a problem, when a more analog one can do the same job. Still, there are reasons we create technology to perform seemingly mundane tasks, so what's actually good and bad about driving with the windows down?

Pros and Cons

  • Fresh air: Driving by the ocean or in nature, nothing compares to the fresh air and fragrances of the outside world that come from driving with your car windows down.
  • Awareness: You can hear what's going on around you clearly, whether it's an ambulance to yield for or the call of an elusive bird you are trying to find.
  • Initial cooling down: Nothing gets rid of hot air trapped in a vehicle that was parked in the sun faster than rolling the windows down and letting the wind blow through the car.
  • Increased fuel consumption: Having the windows down causes significantly more drag, especially at highway speeds, as the air no longer flows over the car's smooth skin, but is interrupted by the window openings. This increased drag impacts MPG.
  • Dust and pollution: Dust, pollen, smoke, and strong smells can enter the cabin without wastehindrance through the open windows.
  • Noise: The rush of buffeting wind, especially at high speed, creates a lot of cabin noise.
  • Still ineffective: On a hot day in traffic with no wind - as is typical summer weather in many cities in the USA's Midwest - open windows will not do much to cool you down.
(Video) Windows Down or Air Conditioning On: Which Is Better for Fuel Economy?

Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (2) unsplash.com

Tips on How to Cool Down Your Car’s Interior Quickly

If your car has been standing in the sun for hours and feels like a sauna when you get in, try the following:

  • Open all the windows immediately
  • Start driving to let the car air out
  • Set the air-conditioning to cold
  • As soon as air-conditioned air arrives, close the windows
  • Don't waste fuel by driving with both an open car window and the air conditioner operating

How Much Does the AC Affect Gas Mileage?

Luckily, there have been multiple studies on this particular subject, so there is a fair amount of data corroborating the findings. Using your air-conditioning uses more gas than opening your windows, especially in city traffic or when driving slowly. At speed, open windows' added drag plays an increasingly important role, but it still wastes less fuel than using the air con. So, how much gas does the AC use? Up to 25% more, especially on short trips. So in the battle of air-conditioning up vs windows down, open windows are better for fuel economy.

Conclusion

What is the moral of the story? Open your windows whenever you can and only use your air-conditioning when you have no other choice, such as on the open road, when nothing else cools you down, or in dusty conditions. This is the best way to save fuel while still enjoying the benefits of air-conditioning when you need it, as permanently leaving the air-conditioning on wastes gas.

(Video) Car AC ON vs Windows Down - Mythbusters

Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (3) Pexels.com

FAQs

When should I use my air-conditioner?

Use it mainly on the highway, where it is inconvenient and noisy to drive with open windows. To save fuel, drive with open windows whenever possible. However, it is still necessary to turn it on every week or two, even if just for a few moments. This helps keep the seals lubricated and prevents the system from developing premature leaks.

Why does my air-conditioner not blow a lot of air anymore?

Chances are good that your cabin filter is blocked and should be replaced. Other possible causes for low flow include frozen evaporator coils or leaky/blocked air ducts.

How do I know whether the air-conditioner is on?

There should be a light glow from the AC button. Climate-control systems should show a snowflake icon or something similar to indicate when the air-conditioner is running. It should have an override, too, to switch it off. You will obviously also feel cool air from the vents.

Does an AC use gas?

ACs use refrigerant gas, yes, and over time pressurized systems like this can begin to leak. Symptoms of a potential refrigerant leak include warm air blowing from the vents or a thin, greasy substance leaking around the compressor. First check for leaks before simply refilling with gas.

(Video) Mythbusters - Save more gas with AC on or Windows down Ans with AC

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Tags: #Land Rover News #Driving Tips

Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (4)

Cobus F. Potgieter

Senior Editor

After completing his studies in Public Relations Management, Cobus' career took him into writing and editing in many fields. But cars were always his obsession, especially the '80s and '90s bangers he loves so much, reciting their specifications, and always telling you what can go wrong with them if you're interested in buying a used one. Which is exactly what he now does at CarBuzz. He'll rattle on about transmission families and unreliable engines ad nauseam. He buys cars simply because he finds them mechanically quirky and interesting, which might explain why he owned a Smart, several ancient luxury sedans, and now runs a small hatchback that "corners on rails" or whatever he muttered under his breath when nobody was listening. He likes blocking the exit and regaling captive colleagues with such information - completely unsolicited.

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Car Windows Down vs Air Conditioning Up? Does Using The AC Affect Gas Mileage? (11)

FAQs

Do you get better gas mileage with the windows down or the AC on? ›

“The rule of thumb is to keep the windows down while on city streets, then resort to air conditioning when you hit the highway,” says Slate writer Brendan Koerner. “Every car has a speed at which rolled-down windows cause so much drag as to decrease fuel economy more than a switched-on AC.

Is running an AC in your car more efficient than opening your windows? ›

The amount varies widely based on the model of car — and based on its speed and outside air temperature — but having AC on at a medium level generally reduces fuel efficiency by somewhere between 3 and 10 percent. On the other hand, having the windows open increases air resistance (or, in physics terms, drag).

Does the air conditioning in your car affect your gas mileage? ›

Under very hot conditions, AC use can reduce a conventional vehicle's fuel economy by more than 25%, particularly on short trips. The AC's effect on hybrids, plug-in hybrids, and electric vehicles (EVs) can be even larger on a percentage basis. Driving with your windows down can also reduce fuel economy.

How can I save gas when driving? ›

20 things You Can Do to Save Gas While Driving
  1. Drive less.
  2. Warm up your car for shorter lengths of time. ...
  3. Buy gas early or late in the day. ...
  4. Slow down and drive steady. ...
  5. Monitor when and how you brake. ...
  6. Turn off the engine. ...
  7. Eliminate wind resistance. ...
  8. Avoid gas stations near the highway.
19 Oct 2017

At what speed are cars most fuel-efficient? ›

7. The Energy Saving Trust says that the most efficient speed you can travel in a car in terms of achieving the best fuel economy is 55-65mph. Any faster, though, and the fuel efficiency decreases rapidly. For example, driving at 85mph uses 40% more fuel than at 70mph (oh, and it's illegal too).

Does having your windows down burn more gas? ›

Having your windows rolled down increases wind resistance, also known as drag, which slows your car down. As a result, it requires more fuel to run.

What AC setting saves gas? ›

Temperature settings: Lower AC temperatures will require more gas than moderate temperature settings, so consider setting your car's AC temperature as high as comfortably possible to save gas.

Does windows Down burn gas? ›

Overall, both studies showed that driving with the windows down has a significant negative effect on the fuel efficiency — more than using the vehicle's air conditioner [source: Hill].

Does cruise control save gas? ›

Generally speaking, yes. Cruise control can help you become more fuel-efficient and can help you save an average of 7-14% on gas thanks to its ability to maintain a continuous speed. In comparison, the constant change in acceleration and deceleration of the driver placing their foot over the pedals can eat more gas.

How do you make your gas last longer? ›

Drive More Efficiently
  1. Go Easy on the Pedal. Speeding, braking, and rapid acceleration waste gas. ...
  2. Slow Down. Gas mileage efficiency tends to decrease above 50 miles per hour. ...
  3. Leave Extras at Home. ...
  4. Use Cruise Control (When Appropriate) ...
  5. Turn off the Car. ...
  6. Check Tire Pressure. ...
  7. Replace Spark Plugs. ...
  8. Check the Alignment.

What are four ways a driver uses less gas when driving? ›

Fuel-efficient driving techniques
  • Accelerate gently. The harder you accelerate the more fuel you use. ...
  • Maintain a steady speed. When your speed dips and bursts, you use more fuel, and spend more money, than you need to. ...
  • Anticipate traffic. ...
  • Avoid high speeds. ...
  • Coast to decelerate.
7 Dec 2021

What speed should I drive to save gas? ›

While vehicles reach optimal fuel economy at different speeds, gas mileage usually decreases rapidly at speeds above 50 miles per hour (mph). For light-duty vehicles, for example, every 5 mph you drive over 50 mph is like paying $0.18 more per gallon of gas (based on the price of gas at $2.63 per gallon).

Does driving at 60 save fuel? ›

“We found that limiting your maximum speed to 60 MPH reduces your fuel consumption by 10%,” said Simon East, CEO of DriveGain, “but that this only adds 2 minutes to the average journey time”. “We find drivers tend to over-estimate how much quicker they will arrive when driving faster”, he added.

What is considered good gas mileage for a car? ›

Generally, a good rule of thumb for gas mileage nowadays is to make sure you are getting at least 23 MPG combined city and highway. However, there are all kinds of factors that will affect the mileage you get and how efficient your vehicle will be.

Does turning off air conditioning save gas? ›

If you turn off your AC and roll your windows down on Burlington highways, it actually uses up more gas than if you kept your AC on. This is because the drag that is produced by rolled-down windows forces your engine to work harder to get you where you're going!

How much extra fuel does AC use? ›

Despite many believing this is a common misconception, air con does in fact increase your fuel consumption. Research has found that by using your air conditioning to control the climate of your vehicle, you can actually increase your fuel consumption by around 8-10%.

Does having windows down waste more gas? ›

Having your windows rolled down increases wind resistance, also known as drag, which slows your car down. As a result, it requires more fuel to run.

Does cruise control save gas? ›

Generally speaking, yes. Cruise control can help you become more fuel-efficient and can help you save an average of 7-14% on gas thanks to its ability to maintain a continuous speed. In comparison, the constant change in acceleration and deceleration of the driver placing their foot over the pedals can eat more gas.

Does driving with windows down use more gas? ›

Overall, both studies showed that driving with the windows down has a significant negative effect on the fuel efficiency — more than using the vehicle's air conditioner [source: Hill].

How much gas does a car use idling with AC? ›

Idling uses up to ½ gallon of fuel per hour (although it varies depending on the type and size of the engine). It may not seem like much, but idling for a few minutes everyday can cost you several dollars per week. MYTH: Engines need to warm up by idling, especially in cold weather.

Does running the AC use more gas Mythbusters? ›

So, according to these tests, AC use does not impact 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.

How much gas does AC use while parked? ›

Q: How Much Fuel Does A Car Use Idling With AC On

If you leave your car idle with your AC on, you will be using between 8% to 10% extra fuel. While it is true that you consume fuel when driving with your AC on, you tend to use more fuel when idling with AC on.

Videos

1. Does your car AC consume fuel ? | RettroDrive |
(Rettrodrive)
2. AC or windows down can lower gas mileage, mechanic says
(WRSP/WCCU FOX 55/27 Illinois)
3. VERIFY: Does Not Using AC in Your Car Save Gas?
(News 19 WLTX)
4. Does Using Your AC Really Use More Gas Than Having Your Windows Down?
(Circuit Catus)
5. Does running the AC in your car actually burn a lot of gas?
(WFAA)
6. How much MORE GAS does your AC use?
(Huntsteven6)

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