How Idling consumes More fuel in Cars?

When they say that idling consumes more fuel, it's the same across the board. Idling the car for more than 30 seconds will use more fuel than if you just shut the car off and restarted it. That's it. It's not complicated. It has nothing to do with the consumption at idle vs in motion.

Inside the engine goes like this. At idle you use little fuel because it only has to maintain about 600 RPM. When you drive at 60MPH your engine is running at about 2000 RPM and needs more fuel to do it. Want to go faster need more fuel pull heavy loads use more fuel want more horsepower need more fuel. It is a heat engine it uses fuel for that heat.

It uses more fuel going somewhere. However, the fuel efficiency of the engine drops like a stone near idle (after all, at idle all the energy of the gasoline does noting useful) because of a technical consideration called the Carnot ratio and because of "pumping losses" - the energy needed to pull air past the nearly closed throttle. The A/C adds useful load but at exremely low efficiency.

However, efficiency is not the same as consumption. It does not take a lot of energy to run the A/C (1-4 hp, depending on temperature, humidity, size of vehicle...). It takes even more energy to drive somewhere, but the efficiency is higher. Bottom line: it costs more to drive than to idle with the A/C on, it costs more to idle with the A/C on than to idle with the A/C off, and it costs more to idle with the A/C off than it does to just shut the engine down. At the end of the day, it is your money to spend as you please.

man really you need to get a better hobby