It is now ‘furnace season’ in many parts of China, with daily temperatures often exceeding 40 degrees Celsius.

On such days, heat gets trapped inside vehicles, causing cabin temperatures to become much higher than outside temperatures. Temperatures can soar to 70deg C which is hot enough to fry an egg.

GM says its vehicles don’t have to endure high heat for long because their vehicles’ air-conditioning systems have been designed to cool down by 40 degrees within just 5 minutes and 45 degrees within 10 minutes, which is faster than many competitor models.

The new Chevrolet Malibu XL sedan available across China, for example, offers dual-zone automatic climate control that allows the driver and front-seat passenger to operate separate temperature settings. The Malibu XL’s rear-seat air outlets help keep the entire cabin cool. These features provide optimal climate-controlled comfort year-round, especially during the hottest months of the year.

Dual-zone automatic climate control aids the more efficient cooling of the interior, particularly if the driver is alone, by minimizing wasted cooling in the passenger compartment. By using air conditioning more efficiently, the driver can put less demand on the engine, resulting in higher fuel efficiency and lower emissions.

GM says its Global Product Development scientists test all vehicle air-conditioning systems in external temperatures of up to 50deg C using state-of-the-art facilities and standardised testing.

“By testing in the harshest temperatures, we are ensuring that our customers enjoy comfortable temperatures inside their vehicles, all the time,” said GM China HVAC Engineering manager Kevin Wang.

Thermal testing of air-conditioning systems typically requires driving test vehicles thousands of kilometres in real-world and simulated environments. GM scientists conduct these tests at climatic test laboratories at its engineering centres around the world, including China. Additional testing is done at the GM Desert Proving Ground in Yuma, Arizona, in the U.S.

In real-world and laboratory environments, vehicles are subjected to high solar load – which refers to the heat generated from maximum exposure to sunlight. The vehicles are then driven at a steady speed to ensure their air conditioning systems are capable of cooling the interior to a comfortable temperature within minutes.

The longer a vehicle sits closed in sunshine, the hotter the interior gets. When it is 32 degrees outside the vehicle, the interior temperature can rise to 51 degrees in just 30 minutes, 56 degrees in 60 minutes and 59 degrees in 90 minutes.

Vehicles with light-colored interiors and exteriors typically cool down more quickly than dark-colored vehicles because darker colors absorb more heat from sunlight. As a result, light-colored vehicles can be about 5 degrees cooler than dark-colored vehicles when subjected to the same solar load. Additionally, tinted glass can help reduce heat load inside vehicles by nearly 80 percent.