With the arrival of heat, keeping the car’s interior at a comfortable temperature becomes almost mandatory. The question is old, but still relevant: is it worth driving around with the windows open or turning on the air conditioning?
At first glance, the answer seems simple. Air conditioning requires energy from the engine and therefore increases fuel consumption. However, the issue does not end there. According to , the impact on consumption depends on the technology of the air conditioning system, the power of the vehicle and, mainly, the speed at which it is traveling.
Air conditioning increases consumption
Operating the air conditioning involves additional strain on the engine, especially in cars with less powerful engines. In these cases, in addition to the increase in consumption, you may also notice some loss of performance. Under normal conditions, driving with the air conditioning on tends to be more expensive than driving with the windows open, especially on urban routes or at lower speeds.
Even so, the most modern systems, with digital climate management, can better optimize the cabin’s cooling. This makes it possible to reduce the effort required and make consumption more efficient than was the case in older systems.
Open windows also have a cost
The idea that opening windows has no impact on consumption is misleading. Although there is no direct expense like air conditioning, there is a loss of aerodynamic efficiency. When the car drives with the windows open, air enters the passenger compartment and increases resistance to movement. The vehicle becomes less efficient and the engine needs to work harder to maintain the same speed.
This impact is not very relevant in the city, but becomes more evident as speed increases. On a state highway or highway, the difference can weigh on consumption.
Speed changes the answer
The rule of thumb involves speed. At low speeds, especially below 50 miles per hour, driving with the windows open may be the most economical solution. In these conditions, aerodynamic loss is still limited and it may be worth avoiding the use of air conditioning, especially if the heat is not extreme.
Once above 80 kilometers per hour, the situation changes. The resistance caused by open windows becomes more significant and can increase consumption. In these cases, using air conditioning tends to be the most efficient and comfortable option.
On the highway, the air conditioning can compensate
On the highway, driving with the windows open greatly affects the car’s aerodynamics. Noise increases, comfort decreases and consumption may increase due to greater air resistance. Therefore, on faster trips, the best solution is to close the windows and use the air conditioning sparingly.
The ideal is to avoid leaving the temperature too low. The greater the difference between the external temperature and the desired temperature inside, the greater the effort on the system. A balanced setting allows you to travel in comfort without increasing consumption too much.
How to use air conditioning without spending so much
Before turning on the air conditioning at maximum, you can open doors or windows for a few seconds to release the hot air accumulated inside the car.
Then, once on the move, you should close the windows and turn on the HVAC system at a reasonable temperature. In many cases, using the automatic function helps keep the cabin comfortable with less effort. It is also important to maintain the system. Dirty filters or lack of gas can reduce efficiency and force the air conditioner to work harder.
What is the best option?
In the city or at low speeds, opening the windows may be the most economical option, as long as the heat is bearable. On fast roads or highways, air conditioning tends to be more suitable, because it avoids aerodynamic loss caused by open windows and guarantees greater comfort.
The answer, therefore, is not the same in all situations. What you spend more depends on the speed, type of car, air conditioning technology and the intensity of the heat. Essentially, below 80 kilometers per hour, open windows can compensate. Above this value, air conditioning used in moderation tends to be the most efficient and safe choice for traveling in comfort.
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