This is a topic of much debate. The fact is that running the Air Conditioner (A/C) really does increase fuel consumption, this is because most vehicle air conditioners require engine power to operate. But there are tricks to improve fuel economy while running your car A/C.
Consider using the “re-circulating” function of your a/c system. This method requires less energy because you are cooling only the air already in your vehicle, not bringing in warmer outside air to be cooled.
When buying a car be sure to ask if a vehicle has an a/c system with an “econo” mode or smart controls that help reduce fuel consumption. This type of air conditioner is found in cars with climate control system.
While on the highway, open windows increase the car’s aerodynamic drag, and that makes the engine work harder which in turn increase fuel consumption. Modern cars are designed to be aerodynamic allowing it to move through the air seamlessly. Consider closing your windows and turning on your A/C. this will reasonably reduce fuel consumption. This short video below shows how aerodynamism works in a car.
Be cool, and don’t over air condition! Just as you would at home, adjust your thermostat settings. Aim for a comfortable setting– not cold.
Manufacturers are developing more efficient a/c system technologies and control strategies to reduce the impact of an a/c system on fuel consumption. For example, some manufacturers have introduced electric a/c systems to improve vehicle fuel efficiency. In the nearest future, even sooner than we think, air conditioning system that improves fuel consumption will be developed.