All cars these days come with an air conditioner. The HVAC system has become one of the basics today as one of the car’s features.
Car’s aircon helps circulate the cool air in the cabin while drawing off the warmness. There are many components involved in making aircon a success and to keep it functioning.
It is easy to understand that since various components contribute to making the AC working, these components must get their power from somewhere.
Today, we are going to discuss how much power car ac draws, and how car aircon get their power.
Contents
- How Much Power Car AC Draws?
- FAQs on How Much Power Car AC Draws
- How much horsepower does a car’s AC compressor actually use?
- Why does turning on the AC make my car feel slower or less responsive?
- Does a car’s AC use more power at idle or while cruising?
- Do electric vehicles (EVs) lose driving range because of AC use?
- Is AC power draw constant, or does it vary as the car cools down?
- Conclusion
How Much Power Car AC Draws?
Ac’s direct power comes from the engine, and the more the AC performs, the more engine is used.
This has a direct impact on the fuel and the total amount of the fuel that would be used depends on how high or low you operate the aircon.
You may have noticed how the car’s engine RPMs increase when the compressor performs heavily.
However, when we talk about how much power ac draws from the engine, there is not a particular answer to that. The amount of power that the engine draws depends on the year and the model of a car.
The General Idea
As a general idea, a car’s ac consumes 1/4 HP or horsepower if you run it low on a normal day.
On a humid or hot day, it can consume somewhere 10 HP when the fan runs on full. Also, it depends on how much you accelerate!
Most cars that manufactured after the year 2000 come with a relay that shuts off the AC when the throttle is wide open. This ensures an ample amount of power for the engine when the acceleration rate gets higher.
Also, it depends on the car too such as if it is a full luxury or a subcompact. Since a subcompact has a relatively smaller engine, it will be more affected during the AC operation than a V8 engine.
Another factor in the total power consumption is whether or not you keep the windows open.
Even if a single window is open when the aircon works, it does affect the overall power used from the engine.
That is why it is always recommended to close all the windows when the AC is functioning.
When one wants to go more economical then he should consider opening the car’s windows while keeping the AC off.
When your car is on speed and you have the windows open, it would be less humid inside, and that way, you can save on fuel.
SEE MORE: The Detailed Explanation on How Aircon Works
FAQs on How Much Power Car AC Draws
How much horsepower does a car’s AC compressor actually use?
Typically between 5 to 10 horsepower (3.7–7.5 kW) when engaged.
Though in small cars it can drop to 3 HP, and in large SUVs or trucks, it can exceed 12 HP under heavy load.
Why does turning on the AC make my car feel slower or less responsive?
Because the compressor adds load to the engine. The ECU often reduces throttle response slightly to balance idle stability and maintain comfort.
Does a car’s AC use more power at idle or while cruising?
At idle, the compressor runs slower, so cooling efficiency drops and it often cycles more frequently, this can spike short-term load on the alternator.
Do electric vehicles (EVs) lose driving range because of AC use?
Yes. AC in EVs can consume 1–3 kW, reducing range by 5–10% depending on cabin size, outside temperature, and efficiency of the heat pump system.
Is AC power draw constant, or does it vary as the car cools down?
It varies!
The system draws maximum power when first turned on, then drops significantly once the cabin reaches the target temperature.
Conclusion
To save even more, you can put all unnecessary accessories to Off, and run AC only. That way you would be having cool air without drawing much power.
So by being a little strategic inside the cabin, one can save the overall cost that you pay for your aircon.
Now you understand how much power car AC draws, and how it can be controlled, we hope you would bring the tips to use.
Read more Maintenance Tips and troubleshoot every issue of your car!
