Here’s How Much Gas Idling Use! (Too Much)

Have you ever left your car running while having a conversation with a friend in the car? Well, that is idling. Idling is when a vehicle owner leaves the engine running while the vehicle is not in motion.

It is a requirement in cases such as being in traffic or observing the red light rules. Let’s be honest, nobody will switch off their engine while waiting for a red light.

But in most situations, idling is not necessary. It’s a habit that drivers must reduce, especially when considering the harmful threats it could pose to our health and environment and not just its effect on their vehicle’s fuel economy. Furthermore, some states passed laws that made idling your car illegal.

How much gas does idling use per hour?

Is it fuel-efficient to idle for hours? First, consider how much gas idling uses compared to when you start and stop a vehicle engine. Researchers have found out that start-stop engines save more fuel compared to a vehicle that’s being idled.

Starting a vehicle’s engine requires very little fuel, which is the same as when idling for about 7 seconds. The amount of gas idling used also depends on the vehicle engine type. When idling, a petrol engine burns gas twice more than a diesel engine. Idling for more than seven seconds is not fuel-efficient for a petrol-built engine.

So, fuel is wasted when stuck in traffic, and the car has been idling for more than seven seconds. The ideal thing to do is to turn off the engine. But in some scenarios, this is not possible or practical.

So, how much gas does idling use per hour?

An Idling 1.5-liter engine uses 0.105 liters in 10 minutes; multiplying that by 60 minutes, we have that an idling 1.5-liter engine uses up to 0.603 liters of fuel per hour. If the engine displacement is larger, it will use more than that. Research also shows that about 4% to 8.7% of the fuel is saved using the start-stop system, ranging from light to heavy traffic.

If idling uses that much per hour, how about some other fuel-efficient ways? Like not idling for extended periods, driving too. When you drive, you cut costs on your gas, and your vehicle performs much better.

How much gas does idling with AC use?

It’s a known fact that driving with the AC on uses more gas than driving without it. How about when the car is parked, but the engine is still in motion? The answer: A lot!! Idling with the AC on actually burns a lot more gas, which should be avoided.

Meanwhile, it depends on a lot of factors. One of the many factors is the size of the vehicle’s engine, as a large engine will use more fuel than a small engine. The amount of gas used idling with the ac on also depends on the weather conditions. On a hot sunny day, the load on the AC is increased but decreases when the outside temperature is lower.

Regardless, leaving your vehicle idling with the AC running consumes 8 to 10% more gas. Turning off the AC while idling will make a significant difference if you’re trying to go low on fuel consumption. The more load the engine has, the more it has to work — resulting in more fuel used.

How much gas does a four-cylinder car use idling?

Having a four-cylinder car implies four cylinders or chambers in the engine. These types of engines are usually found in smaller cars. They are cheaper to maintain, have fewer moving parts and are simpler. Another advantage is that a four-cylinder engine tends to be more fuel efficient when compared to a larger engine size.

So, how much gas exactly does it use?

While idling, a 4-cylinder engine consumes 1.2 liters of gas per hour. This implies that it uses 0.02 liter of gas idling for every minute. Imagine idling your vehicle every day for an hour, for a week. That’s about 8.5 liters of gas. That’s right. 8.5 liters a week while your car is not in motion but idling! What do you think?

How much gas does a 6-cylinder car use idling?

On the other hand, a 6-cylinder engine or an inline six-cylinder engine is used in larger cars. It implies that the engine has six cylinders or chambers powering it. Since a 6-cylinder engine has a higher performance, they are best suited for sports cars. Because of its higher performance, more gas is required.

A 6-cylinder engine is equivalent to a 3 to 3.8-liter engine. And for every 10 mins of idling, this 3.8- liter engine consumes about 0.36 liters of gas. This implies that for every hour of idle, it uses over 2.17 liters of gas. Imagine idling your car for 30 minutes daily without moving an inch! I bet you’d want to reconsider.

So, does idling use as much gas as driving?

Leaving your vehicle idling for an extended period is undoubtedly a waste of gas. The gas consumed idling can be used for driving. Two minutes of idling is the same as driving a mile. Gas is already burnt up without even moving the car! Idling is equivalent to zero miles per hour, and that is if you decide to idle your vehicle for an hour.

Moreover, your vehicle’s engine warms up quicker when you drive than idling. Constant idling only strains your car battery and doesn’t allow it to charge. When you sit in a car, and it idles for more than a couple of minutes, the best thing to do is to turn it off. Leaving your car idling for an hour uses about 1⁄2 gallon of gas, while driving is about 0.16 gallon of gas per hour. Apart from the fact that it wastes gas, frequent idling can also cause wear and tear resulting in a higher maintenance cost.

Is it OK to idle your car for hours?

Cars are made to be driven. They are designed to move, allowing air to flow into the engine. They are not designed to stay still and consume gas. Let’s consider reasons why you shouldn’t leave your car idling for extended periods;

  • Idling for hours can damage some components over time; you will be stressing the cooling system, the engine, and the transmission. It’ll wear the transmission, engine, battery, and the engine components such as the plugs, cylinders, and exhaust pipes, resulting in extra costs to maintain your vehicle.
  • It wastes gas. Idling for just 10 seconds uses more gas than restarting an engine. Idling for about 2 minutes is equivalent to a mile which is a lot of gas in such little time. Now, imagine idling for an hour or two hours; you’ll be wasting gas that could be used to drive the car for several miles.
  • Leaving your car idling brings about environmental pollution. Idling, as it seems, increases the amount of hazardous gasses in the air, such as; carbon monoxide and nitrogen oxides, posing threats to humans and animals alike. These gasses, for example, carbon monoxide, is a poisonous gas that affects the respiratory tract, leading to asthma and other lung diseases. It also affects the atmosphere, making it almost impossible to cleanse itself of other polluting gasses. Thus, when released, nitrogen oxide binds with oxygen to form nitrogen dioxide, which is also a poisonous gas. Therefore, turning off your idling engines brings about healthier air by decreasing the number of toxic pollutants in the atmosphere.
  • Cutting down on idling help saves money. If you were to cut 10 mins of idling a day, you could save around 8.9 gallons of gas per year. So instead of idling, why not switch to restarting your vehicle and also save yourself some extra cost of wear and tear?
  • Frequent idling burns up oil so fast. That means there will have to be a frequent oil change. But when ignored, this will pose potential damage to the engine. All these lead to decreased performance of the vehicle.


In reality, everyone is looking for ways to cut down on the cost of fuel. You could spend the extra money on other things; thus, you might want to reduce your idling to save up on gas. Besides the amount of gas, think about the damage it could pose to your health and those around you, especially its effect on the environment. Idling for a few minutes might not damage your vehicle, but it discharges about a pound of carbon monoxide into the air.

Additionally, not leaving your car idling as often could prevent a lot of damage to your engine; hence, do your car a favor and don’t idle for an extended period. Make it a priority; then, always remember to turn the key off when you idle for more than 10 seconds when parked or in traffic.