Hyundai cooling film takes heat off police buses

For police officers spending long hours in buses during Korea’s summer heat, relief may soon come not from stronger air conditioning but from a nearly transparent film on the windows.

Hyundai Motor Group said Wednesday it has applied its Nano Cooling Film to two Universe buses operated by the 1st Mobile Unit of the Seoul Metropolitan Police Agency.

The buses serve as mobile offices and living spaces for officers responding to demonstrations and other public safety duties, making heat inside the vehicles a persistent concern during hot weather.

Because dark window tinting is difficult to use on police buses for operational and regulatory reasons, officers can be particularly exposed to high temperatures while carrying out their duties.

Nano Cooling Film is designed to reflect solar heat while also radiating infrared heat from inside a vehicle to the outside, according to Hyundai Motor Group.

The three-layer material includes two layers that reflect near-infrared wavelengths from sunlight and another layer that releases mid-infrared wavelengths from inside the vehicle.

Hyundai Motor Group said it installed film with 90 percent light transmittance on the side and rear windows of the two buses, which have since returned to police operations.

In comparison tests conducted on Universe buses, vehicles fitted with the film maintained interior temperatures about 2 to 3 degrees Celsius lower on average than vehicles without it, although results varied with weather and sunlight.

The temperature difference approached 7 degrees Celsius in the driver’s area, where sunlight was more intense.

Hyundai Motor Group said lowering a Universe bus’s interior temperature by 1 degree Celsius requires about 1.6 kilowatt-hours of electricity, suggesting the film could also reduce energy consumption and carbon emissions.

The company plans to monitor the buses for one year before deciding whether to move toward full-scale production, focusing on cooling performance and product quality.

The technology previously drew international attention through Hyundai Motor’s Made Cooler By Hyundai campaign in Lahore, Pakistan, where the company provided Nano Cooling Film to more than 70 vehicles in 2024.

Hyundai Motor Group said the campaign later led to international recognition, including awards at the 2024 London International Awards and The One Show 2025.

Lee Min-jae, a principal researcher at Hyundai Motor and Kia’s Basic Materials Research Center, said the technology could help officers working in extreme heat and that continued real-world testing would improve its performance.

This article was published with the assistance of generative AI and edited by The Korea Times.