Yes, running the air conditioning (AC) in a car does waste (or use more) gas, though “waste” may not be the right word—it’s more about extra fuel consumption due to the added workload on the engine. The AC system relies on a component called the compressor, which is powered by the car’s engine. When the AC is turned on, it engages the compressor, which requires additional energy, causing the engine to burn more fuel to maintain power and performance.
How Much Gas Does the AC Use?
The amount of extra gas used by the AC varies depending on:
- Vehicle type and engine size
- Driving conditions (city vs. highway)
- How hard the AC system works (low vs. high fan speeds, temperature settings)
- Outside temperature (hotter weather requires the AC to work harder)
On average, using the AC can:
- Lower fuel economy by 5% to 20%.
- Consume 0.2 to 1 gallon of fuel per hour when idling, depending on the car.
Why Does the AC Use More Gas?
1. Compressor Load
The AC compressor is mechanically driven by the engine. When it runs, the compressor increases the engine’s workload, and the engine needs to burn more fuel to power both the car and the AC system.
2. Blower Motor and Fans
While the blower fan doesn’t use much power by itself, it does require electrical energy, which comes from the alternator, powered by the engine.
However, the major fuel use increase comes from the compressor, not the fan.
AC vs. Rolling Down the Windows: Which Wastes More Gas?
- At low speeds (under 40 mph): Rolling down the windows can be more fuel-efficient than using the AC.
- At high speeds (50 mph and up): Open windows create aerodynamic drag, which can decrease fuel efficiency as much as or more than using the AC.
Tips to Reduce Fuel Consumption When Using AC
- Use recirculation mode: This cools already-cool air, making the AC work less.
- Park in the shade or use a sunshade to keep the cabin cooler before starting the AC.
- Avoid idling with the AC on—it burns fuel without moving the car.
- Set moderate temperatures instead of blasting the coldest setting.
What About Hybrids and Electric Cars?
- Hybrids: Often have electric compressors, but if the battery runs low, the gas engine may run more often to power the AC.
- Electric vehicles (EVs): The AC uses battery power, which reduces driving range, though there’s no gasoline consumption.
Final Answer
Yes, the AC on a car does use more gas, because it puts an extra load on the engine. While modern cars are more efficient, running the AC still causes additional fuel consumption—how much depends on how and where you drive. Smart AC use can help minimize its impact on your fuel economy.
Also Check:
• Does Air Conditioning Waste Gas in a Car?
