When driving your car in hot weather, you probably don’t overthink about anything other than a cooler cabin when you hit the “AC” button on your dashboard. After all, as long as cold air comes out of the vents, it doesn’t matter what your car’s air conditioning system is doing, right?
Well, turning on your car’s AC can affect fuel economy slightly. But it can also affect your car’s horsepower output. But how much power does AC pull from the engine?
How the Car AC System Pulls Power From the Engine
Your car’s air conditioning system has multiple parts and is connected to the engine via a drive belt that runs the alternator and water pump. When the AC system starts, you might notice that the engine RPM increases slightly.
According to experts, the car does this to offset the power drawn by the AC system, so there’s no doubt that the system robs your engine of horsepower when activated.
The amount of Horsepower a Car Loses When the AC is On
The amount of power an engine loses can vary depending on what type of car you drive. Smaller engines might not lose as much power, while larger engines can lose more since the power loss is a percentage of the overall horsepower output.
According to testing done by a YouTuber, “Sikky,” the average amount of power and torque lost to the drive wheels is around ten each across the board. The YouTuber strapped a Lexus IS-F to a Dynapack dynamometer, measuring horsepower at the car’s hubs.
According to his testing, the Lexus IS-F produced 363 hp with the AC on, which jumped up to 372 when the AC was turned off. And while that power loss could be relevant to that specific car — especially since it has a large V8 engine – we can assume that you’ll find the same type of power loss on most cars you drive.
Handling Car Power Loss Due to AC
If you want to ensure that you’re maximizing your car’s full power potential but still want the luxury of having AC, then you can use some of these simple practices:
- Only use your car’s air conditioning system when needed. There’s an “on/off” button, after all.
- If your car is equipped with automatic climate control, you can set the interior temperature to the same as the outside temperature. Doing so will ensure that the AC system doesn’t activate as frequently.
- Ensure the air conditioning system is switched off when you start the car. It won’t make a huge difference, but can still save your engine some power.
Conclusion
The next time you turn your car’s air conditioning system on, you’ll likely notice the loss of power. Although it’s not enough of a loss to prevent you from driving up a hill, it’s still noticeable. Fortunately, there are ways to circumvent the power loss, even if it is only ten horsepower.
