Is the Sunshade Film on the Windshield Not as Good at Heat Insulation as the Side and Rear Windows?
4 Answers
Sunshade film on the windshield is not as good at heat insulation as the side and rear windows; the windshield primarily focuses on high light transmittance. Automotive Window Tinting: This involves applying a thin film to the vehicle's front and rear windshields, side windows, and sometimes the sunroof. This film is commonly referred to as sunshade film or heat insulation film. Functions of Automotive Window Tinting: The main purposes are to block ultraviolet rays, partially reduce heat, prevent injuries from shattered glass, reduce glare, and, due to the one-way visibility feature of the film, protect personal privacy. Additionally, it helps minimize damage to interior items and passengers caused by UV exposure. By reflecting sunlight physically, it lowers the interior temperature, reducing the need for air conditioning, thereby improving fuel efficiency and saving costs.
Having driven for over 20 years, I've noticed that the heat insulation effect of the front windshield sun film is often inferior to that of the side and rear windows. During summer when the sun shines directly, the front windshield area becomes scorching hot to the touch, while the side and rear windows, with their darker and thicker films, provide noticeably better heat insulation. This is primarily due to safety regulations requiring high light transmittance for front windshield films—at least 70%—to ensure clear driving visibility and prevent accidents. Thinner film materials result in weaker heat blockage. I recommend car owners opt for professional-grade front windshield-specific films, such as those with metal or ceramic coatings. Although more expensive, they can somewhat improve heat insulation. Regularly cleaning the film surface to reduce dust blocking infrared rays can also slightly enhance comfort. On long drives, I prefer turning on the air conditioning in advance to cool down the car, minimizing discomfort from uneven temperatures. After all, safety comes first—don’t skimp on quality by using inferior films.
As someone who just got a new car half a year ago, I feel the heat insulation of the front windshield sun film is noticeably inferior to the side and rear windows. Every time I drive, the sunlight coming through the front windshield heats up the dashboard to a scorching level, forcing me to turn up the air conditioning, while the side and rear windows remain much cooler. A friend mentioned this is due to the film's design constraints—the front windshield requires high light transmittance, resulting in lower heat insulation rates. I personally think switching to a film with strong UV protection could help somewhat, but it comes with a significant cost increase. I recommend checking the heat insulation parameters on the film label; for the side and rear windows, choosing a darker film with 40% light transmittance offers better heat blockage. When parking daily, using a windshield cover or sunshade can reduce heat accumulation. If the budget allows, upgrading the front windshield film should be a priority, as driving comfort affects mood and energy levels. Also, don’t overlook air conditioning maintenance—cleaning the filter can improve cooling efficiency and compensate for insufficient heat insulation.
The heat insulation performance of solar films depends on light transmittance and film thickness. The windshield film requires high light transmittance, typically above 70% to ensure safe visibility, resulting in weaker heat insulation. In contrast, side and rear windows can use films with lower light transmittance to block more heat. When choosing, prioritize safety-compliant products. New technologies such as infrared-blocking films can balance both aspects but come at a higher cost. It is recommended to test the insulation difference before and after installation and pay attention to material durability.
