Does AC Use Gas: The Money-Saving Myth Debunked (2019)

Gas prices are no joke. They're getting more expensive by the day. For those who want to live cheap, the creeping gas prices are hurting the bank account.

I hear you and completely understand where you're coming from.

Seriously, I've got two cars (one a family van and an old Ford that I use to go to work), and both of them can eat up gas.

One thing that I've tried to do is limit the use of the air condition. Either you've done this or contemplated on doing this. I don't blame you.

After all, with gas prices hovering near $4 a gallon, I might as well get the most out of my gas. I know you share the same sentiment.

But I asked myself if doing this can actually save money.

This is where this post came to life, and you'll find this informative and worth your time.

If you are ready:

Read on and find out the answer to the question, “Does car AC use gas?”!

Does AC use gas?

Let's get straight to the point of this post.

The answer is yes (but with caveats).

Like many of your car's features, the air conditioning system uses gas. The AC draws its power from the alternator – this is powered by the engine.

Since gas is needed to power and runs the engine, then, that means that your AC does eat up gas (directly or indirectly speaking).

Does AC run on gas even when you're not using it?

Typically, the answer is to this question is no.

But in certain cases, AC still runs on gas even when you're not using it. This means that in certain situations, using the AC is more efficient than not using it.

To know more about how a car's AC system works and its role in gas mileage, read the information below:

How Car AC Works

Air conditioning works the same way for all cars. Basically, all AC systems run on a high-pressure gas called refrigerant.

The following are the parts/systems used to make up the air conditioning system:

• Compressor: This part simply compresses the refrigerant into a fluid. This way, the refrigerant flows effectively through a line to the condenser.
• Condenser: This part basically removes the heat part from the refrigerant and directly pushes the refrigerant along to the orifice tube or the expansion valve.
• Expansion valve or orifice tube: This part helps return the refrigerant to its original state (gaseous) and moves it to the accumulator or the receiver/drier.
• Receiver/drier or accumulator: This part simply removes the moisture coming out from the refrigerant and, then, transfer it to the evaporator.
• Evaporator: This part, then, pulls heat that is coming from the air passing through its core and, then, transfers the heat into the refrigerant. This results in cold air flowing past the evaporator.

What are other ways to save money on gas?

If you're a frugal person like I am, it all comes down to saving money. If you're looking for ways to save money on gas, here are they:

• Use gas apps. There's no better way to save money that getting cheap gas. Just search ‘gas near me‘ and you'll find the gas station nearest you that sells the lowest-priced gas.
• Warm your car up for shorter lengths of time. Don't let your car run idle for more than 30 seconds. If you run it over this time, you're basically wasting fuel. Believe it or not, engines of many modern cars don't necessarily need to run for an extended time period to warm up.
• Find programs that offer free gas cards. There are grocery stores, websites, among others that offer free gift cards and even free PayPal money so you can buy your gas cards for free. Take advantage of those.
• Slow down and drive steadily. Sure, driving fast can be fun, but it sure does eat up gas as driving fast increases drag, which, then, increases fuel consumption. Basically, aside from your AC burning gas, not slowing down and driving steadily can eat up your car gas consumption.
• Turn off the engine. Idling is just a waste of gas. If you're parked and are waiting for someone or something for 30 seconds or less, it's best to turn off your engine to not waste gas (and save money).
• Eliminate any wind resistance. Aside from not rolling down your window, take anything that increases drag. These include car racks, carriers, just to name a few. These can reduce fuel efficiency.

Can a car that's using AC be fuel-efficient?

So, if the car AC runs on gas, can a car using AC be fuel-efficient?

There are several factors that can affect a car's fuel efficiency. The answer, however, may come as a shock to you.

Generally, using your car's AC can actually lower your car's fuel efficiency by roughly 3 miles a gallon depending on your car's size and age.

In a nutshell, AC will lower your car's efficiency as it diverts energy from the engine itself to power the car.

Imagine 3 people using the same internet connection vice 20 people using the same internet connection. Chances are these 3 people would be getting a faster connection.

So, if you're asking the question “Does AC run on gas?” or “Does the fuel-efficiency get affected?”, the answer is yes.

Believe it or not:

There's an exception to the rule though.

The science behind it is that the open windows can and will increase aerodynamic drag. What this means is that the engine will have to work harder, thus, will need to burn more gas.

So, if you're asking the question of “Does AC use gas?” or more specific question of “Does your AC waste gas?”, the answer would be yes but your car consumes less gas when your AC is on while driving on highways than when your windows rolled down and you're driving on the highways.

So, which is more efficient, AC on or windows down?

According to The Society of Automotive Engineers (SAE), driving with your car's windows up and the AC on is generally a better choice when it comes to fuel-efficiency.

For the sedan, efficiency is reduced by 20% when windows are down. On the other hand, efficiency is only reduced by 8% with an SUV with windows down. This proves that fuel efficiency varies from one type of car to another.

When driving at speed of at least 55 miles/hr (with windows down), the fuel efficiency decreases by 20% or more. This means that it's best to use AC when traveling at higher speeds.

So, when it comes to fuel-efficiency, the question isn't about “Does running the AC use gas?” but it's more like “which option is better (i.e., options between windows rolled down or AC running)?”

That all said, if you're running at a lower speed (i.e., speed less than 55 miles per hour), it's more fuel-efficient to roll down the window.

Do you save gas by not using air conditioning?

The answer is no or barely. Regardless of what option you choose (i.e., windows roll down or AC on), there's no method to cool your own car that doesn't lower your car fuel's efficiency.

Truth be told, even just turning on and off your car burns gas.

Read: Get Paid To Walk: 13 Sneaky Ways To Do It (2019)

How much gas does AC use?

Either the option of rolling down your window or turning your AC on will eat up gas.

But turning your AC on will easily increase fuel consumption by 8-10% (under normal weather or condition).

Under very hot conditions, air conditioner use can reduce a vehicle's fuel efficiency by more than 25% – particular on short trips or in-town or in-city travels.

So, if you're asking the question “Does AC use gas during very hot weather?”, the answer is a definite yes.

What should I do to improve my car's fuel efficiency during hot weather?

So now you know running your AC during very hot weather can cause fuel economy to decrease, you'd probably be asking what you can do to improve such economy to save money on gas.

Here are the answers:

• At lower speeds, roll down your car's windows; Opt for AC for highway speeds
• Park in the shade or just use a sunshade to less the heat that's coming in your car
• Don't use AC (or lessen the use of it) if  you don't need to
• When your car is hot, to begin with, roll down your window to allow hot air to escape. Only after then it is advisable to turn your air conditioner on.
• Most AC systems will cool the vehicle once the vehicle is running on the road. This means that you turn the AC on after you drive
• Read your car's owner manual so you can fully-understand your AC system. The more you know about it, the more informed you are on what your AC system has, capable of, etc.

What are other ways to save money on gas?

If you're a frugal person like I am, it all comes down to saving money. If you're looking for ways to save money on gas, here are they:

• Warm your car up for shorter lengths of time. Don't let your car run idle for more than 30 seconds. If you run it over this time, you're basically wasting fuel. Believe it or not, engines of many modern cars don't necessarily need to run for an extended time period to warm up.
• Slow down and drive steadily. Sure, driving fast can be fun, but it sure does eat up gas as driving fast increases drag, which, then, increases fuel consumption. Basically, aside from your AC burning gas, not slowing down and driving steadily can eat up your car gas consumption.
• Turn off the engine. Idling is just a waste of gas. If you're parked and are waiting for someone or something for 30 seconds or less, it's best to turn off your engine to not waste gas (and save money).
• Eliminate any wind resistance. Aside from not rolling down your window, take anything that increases drag. These include car racks, carriers, just to name a few. These can reduce fuel efficiency.

Does car AC use gas?: Conclusion

Now, you know that car AC uses gas directly or indirectly. You now also know when the best time is to roll down your window or use your AC to burn less gas.

You've also learned other ways to save money on gas (on a normal condition or when the weather is very hot).

But one thing is true:

Regardless of which option you choose (i.e., drive with rolled-down window or with AC on), there's no method to cool your car that won't lower the car fuel efficiency.

I say, choose the one that makes you comfortable while costing you the least amount of gas use.

What was your thought about AC using or not using gas? Did you think that one option (i.e., rolling down the car window) is better than the other option when it comes to burning gas the least possible way?