Efficient air conditioning use reduces summer fuel costs: Study

Today, it's hard to imagine travelling by car without air conditioning. Nevertheless, every bit of saving is invaluable in an era of rising fuel prices. Specialists from SAE International conducted studies showing that intelligent use of air conditioning can bring tangible benefits.

Some people drive in the summer with the air conditioning constantly on and set to one temperature. During heatwaves, driving in a cabin with a bearable temperature is more pleasant and safer because it's easier for drivers to maintain focus and good reaction time. On the other hand, motorists value the comfort of a cooled car but also remember their fuel consumption. Is it possible to reconcile these issues?

Engineers at SAE International (Society of Automotive Engineers) emphasize that proper air conditioning use minimizes fuel consumption, while improper use leads to a noticeable rise in consumption. Experts advise how to cool the vehicle's interior efficiently while reducing costs. Taxi drivers also confirm this.

Many of them refrain from using air conditioning, fearing increased fuel costs, which directly affects their income. The average fuel consumption can increase by 80 to 130 millilitres per 100 kilometres. For small engines, this increase is even more noticeable. One driver of a nearly new Dacia Logan told me that in the summer, he doesn't use the air conditioning because his small engine consumes as much as 15 litres per 100 kilometres in the city (LPG). Without air conditioning, consumption drops to 9 to 11 litres per 100 kilometres.

SAE International specialists recommend opening windows to cool the car's interior but only at speeds below 70 km/h. In such a situation, air exchange is effective, with minimal air resistance, which does not significantly impact fuel consumption.

However, when speed exceeds 85 km/h, opening windows can increase fuel consumption by up to 20 percent. This is confirmed by studies by the international Society of Automotive Engineers.

At higher speeds, air conditioning is not as significant a burden, making it more cost-effective to use it rather than opening windows and worsening the vehicle's aerodynamics. Aerodynamics play a key role in fuel consumption at high speeds.

• at low speeds (city driving), open windows and turn off the air conditioning;
• at higher speeds, close windows and use air conditioning;
• turn on air conditioning only when it is really hot;
• do not set the air conditioning to a very low temperature;
• park in the shade to keep the car cooler, making air conditioning unnecessary;
• after starting, open windows but turn on air conditioning only after a few minutes, once the interior has aired out;
• avoid using air conditioning when the car is stationary;
• Cool the interior before disconnecting from the charger in cars with batteries (electric and plug-in hybrids).