Imagine a car that stays cool even when parked under the scorching Florida sun. That’s what Japanese automaker Nissan aims to achieve with its innovative heat-reflecting white paint. The new technology aims to cool the exterior of its cars by up to 22 degrees Fahrenheit and the interiors by 9 degrees Fahrenheit, according to the company. The ultimate goal? To avoid the typical overheating that comes with parking a car in the sun while reducing air conditioning usage. This is part of a larger push by Nissan—and the auto industry—to increase the efficiency of cars amid growing sustainability concerns in a warming climate.
“My dream is to create cooler cars without consuming energy,” said Susumu Miura, senior manager of the advanced materials and processing laboratory at the Nissan Research Center. “This is especially important in the EV era, where the load from running air-conditioning in summer can have a sizable impact on the state of charge.”
Nissan introduced the paint, which is six times as thick as typical car paint, in November 2023 at the Tokyo International Air Terminal at Haneda for a 12-month trial. Partnering with energy tech company Radi-Cool, it applied its cooling paint to airport service vehicles. Miura hopes Nissan will adapt the paint application to commercial vehicles.
Climate-Conscious Vehicles: The Future of Auto Industry
Increasingly, the technology is becoming appealing as the push for climate-conscious vehicles gains momentum. Toyota is also experimenting with paint that has the potential to cool cabin temperatures. In 2021, a team of Purdue University engineers created the world’s whitest white paint that can reflect over 98% of sunlight. A year later, the team developed a thinner version of the paint that’s able to coat airplanes, cars, and space shuttles.
But what makes Nissan’s cooling paint effective? The secret lies in two particles: one that reflects near-infrared rays that typically cause normal paint to absorb heat, and another that creates electromagnetic waves to deflect the heat.
Reflecting the Future: The Science Behind the Paint
“It has basically combined the light from different wavelengths all together, so you reflect the light on all different angles of different wavelengths,” explained Shu Yang, a professor of materials science and engineering at the University of Pennsylvania. Yang likens the paint to sunscreen, which both absorbs and reflects UV rays from the skin. Even the materials within the paint share similarities with sunscreen, such as titanium oxide, the foundational compound in many of the cooling technologies that reflect heat. While the paint appears white, it’s not due to pigment added to the paint; it’s a result of the structural particles used to create the paint itself.
Looking Forward: Challenges and Considerations
Despite the potential of reflective white paint as a cooling solution, several questions remain about how to enhance this technology in the future. For eco-conscious Nissan consumers who wish to add a colorful flare to their cool cars, the cooling paint will remain white as material scientists continue to identify the optimal particle size to reflect light and heat. The end goal is likely to develop an effective translucent paint that can coat colorful car pigments.
However, there’s more to this issue than just developing cooling paint. There are still many scientific unknowns regarding how and why certain colors reflect and absorb heat. While the general scientific rule states that light colors reflect heat and dark colors absorb it, there are still anomalies, like the deep purple eggplant, which remains cool to the touch.
Moreover, material scientists warn that even technological discoveries and improvements to these technologies offer limited solutions to climate change. The compounds like barium sulfate require mining and extraction, which produce higher carbon emissions.
As Jeremy Munday, an electrical and computer engineering professor at the University of California at Davis, puts it, painting cars with reflective white paint is just a drop in the bucket of addressing the impact of greenhouse gasses being pumped into and trapped inside the atmosphere.
“This is definitely not a long-term solution to the climate problem,” Munday told the New York Times. “This is something you can do short term to mitigate worse problems while trying to get everything under control.”
As we navigate the ever-evolving world of technology and sustainability, it’s clear that companies like Nissan are taking steps towards making our world a cooler place. Yet, it’s important to remember that these are just steps on a much longer journey towards a truly sustainable future.
