Does Car AC Use Gas?

AC button in car 

There's an old joke from the time before air conditioning was standard on cars. You've probably heard your parents or grandparents say the original air conditioning for a car was 4x60, or four windows rolled down at 60 mph. Thank goodness for modern air conditioning that makes summer trips more manageable. Do you have questions about whether the air conditioning system on your next road trip could lower your vehicle's fuel economy? We've got answers.

So, does car AC use gas every time the temperature soars in Stratham or Nashua? The answer is yes. Even though we don't get scorching summers very often here, it's a good idea to use the air conditioning on warm days because the glass windows of your vehicle act like a greenhouse.

The AC system in your car does consume fuel because of how it operates. Like many of your car's features, the air conditioning is powered by the alternator, which in turn is powered by the engine as it turns the serpentine belt. 

In this guide from the Audi Stratham service center, learn why AC uses gas. You'll also discover what you do to boost gas mileage when you hit the road this summer.

How Car AC Works 

No matter what make and model you drive in Concord, the air conditioning system works in much the same way. All vehicles employ a high-pressure gas called refrigerant to power the AC. The serpentine belt turns the mechanism that operates the air conditioner. The serpentine belt turns when it runs on gasoline, which makes the air conditioner cold. If you just run the accessories mode on your vehicle's ignition, the air conditioner won't run cold because the serpentine belt doesn't turn.

The air conditioning system in your vehicle comprises the following parts:

  • Compressor - Compresses the refrigerant into a fluid, allowing it to flow freely to the condenser. 
  • Condenser - Lowers the temperature of the refrigerant and sends it to the expansion valve or orifice tube. 
  • Expansion Valve or Orifice Tube - Reverts the refrigerant to its original gaseous state and delivers it to the receiver/drier (the accumulator). This helps keep the refrigerant in a usable form over and over.
  • Accumulator - Lowers the moisture content of the refrigerant and delivers it to the evaporator. 
  • Evaporator - Extracts heat from the air that passes through its core and transfers the heat to the refrigerant. As a result, cooled air begins to flow from the evaporator. This tightly controlled system usually works perfectly among all of its parts.

All of these parts keep the refrigerant and air conditioning working as efficiently as possible. The AC does burn car gas to maintain this process and move the parts. If there are problems with the system or you feel warm air coming in, it could be due to a leak in the tubing or refrigerant system. The warm air could also be caused by a broken serpentine belt, which is another problem entirely because you'll notice the vehicle is harder to turn, and the battery light will come on.

Can Using Car AC Be Fuel-Efficient? 

Yes, it can be, depending on how and when you use the air conditioning. Using your car's AC is more fuel-efficient than rolling down the windows at higher speeds! According to the EPA, leaving your windows down when you hit highway speeds makes aerodynamic drag worse and forces your engine to work harder as you move down the highway. This becomes a problem when you reach speeds of around 55 mph. At this point, your engine works harder and uses more gas than if you run the AC at full blast. It's better to run the AC when on the highway to keep your passengers comfortable during the summer.

So, yes, your air conditioning in the car does use gas. It might reduce your fuel efficiency by as much as 20% at some points. It depends on driving conditions. However, the Society of Automotive Engineers (SAE) discovered rolling down windows on an SUV reduced its fuel efficiency by 8% when traveling at 55 mph. On a sleeker and more aerodynamic sedan, fuel efficiency was reduced by 20% with the windows down.

The basics of the AC and gasoline fuel efficiency: Drive with windows down below 55 mph before turning on the air conditioning with the windows up.

Other Ways to Improve Fuel Economy

Does AC burn car gas equally no matter what, or are there ways to improve fuel efficiency? You have plenty of ways to improve your fuel efficiency, including rolling up your windows while you roll on down the highway.

There are several ways to boost efficiency while the AC is running:

  • Brake gradually
  • Use high-quality engine oil or synthetic oil
  • Don't pack too many heavy items to reduce your vehicle's overall weight
  • Ensure proper tire alignment and inflation
  • Avoid idling for longer than 30 seconds 
  • Use a sunshade when parked in direct sun
  • Reduce speed and drive in a higher gear 

Test Drive Fuel-Efficient Vehicles at Audi Stratham 

Does air conditioning in the car use gas? Yes, it's necessary to keep your vehicle's cabin cool. In an EV, you won't have to worry about using more gas. But the AC would use more electricity and drain the battery quicker.

If you have questions about vehicle maintenance or repairs, the team at Audi Stratham is ready to help in any way we can! Contact us to speak with an experienced technician. We'll give you tips about DIY car care, maintenance, or repairs. You can also visit us in Stratham to schedule service for brake pad replacement, tire rotation, and more.