Summer presents a major challenge for new energy vehicle owners with panoramic sunroofs—keeping the interior cool and insulated from heat. So, what’s your sunroof missing when it comes to staying comfortable in hot weather? Let’s explore sunlight and the concept of Total Solar Transmittance (TTS).

The Main Reasons for Heat Build-Up Inside the Car

Sunlight consists primarily of visible light, infrared and ultraviolet rays.

When you sit in an ordinary car, excessive visible light and infrared rays penetrate the glass and enter the interior, causing objects to heat up. This is the primary reason for the stifling heat inside the car.

Reducing the amount of visible light and infrared rays (solar heat energy) entering the car is key to effective heat insulation.

While ordinary sunroof glass can block some infrared rays and visible light, achieving better heat insulation often requires the addition of window films. However, this compromises the transparency of the glass, making the interior dim and oppressive. Most ordinary sunroofs force a trade-off between transparency and heat insulation.

How to Measure the Heat Insulation Performance of Sunroof Glass

In optics science , Total Solar Transmittance (TTS) measures the heat insulation performance of glass. It accounts for the energy that directly passes through the glass into the car, the energy reflected by the glass, and the energy absorbed and re-radiated as heat. A lower TTS value signifies better heat insulation.

To enhance heat insulation, it’s essential to reduce the direct transmission of solar energy, increase solar reflectivity, and improve the glass’s ability to absorb and dissipate heat effectively.

The Secret Behind Ambilight EC Smart Dimming Sunroof’s Heat Insulation

The Ambilight EC smart dimming sunroof enhances heat insulation by integrating a crucial EC film between two layers of glass. This film expands the absorption and reflection range to include visible light, infrared rays, and ultraviolet rays. By dynamically adjusting light transmission and heat transfer, it effectively reduces the amount of light and heat entering the vehicle.

Ambilight’s EC smart dimming film features a multi-layered nanoscale coating with a “sandwich structure” design. With smart dimming, its TTS value ranges from 12.2% (dark state) to 13.7% (bright state), delivering heat insulation performance between 86.3% (bright state) and 87.8% (dark state). Beyond superior heat insulation, EC technology ensures the glass remains clear and transparent during dimming, maintaining an unobstructed view.

Experiments show that under identical conditions, after one minute of infrared heating, the temperature of the Ambilight EC smart dimming film was 6.6°C lower than white glass with a 3M heat-insulating film and 12.8°C lower than standard white glass.

According to authoritative reports, the NIO EC6 equipped with Ambilight EC smart dimming sunroof outperformed a new energy vehicle brand’s ordinary sunroof in several aspects:

• Heat Insulation Performance Comparison: The EC sunroof demonstrated superior heat insulation, with slower temperature rise rates and lower peak temperatures compared to the multinational brand’s sunroof.

• Cooling Performance Comparison: Under continuous exposure to sunlight, the EC sunroof achieved rapid cooling, reducing the temperature to room temperature within 20 minutes and reaching an ideal temperature within 45 minutes.

• Overall Thermal Comfort Comparison: Under the same driving conditions, the average temperature of the multinational brand’s sunroof was 13°C higher than that of the EC6.

• Radiation Resistance Comparison: During the sunlight exposure phase, the dummy test showed that the EC6 cabin blocked twice as much solar energy as the multinational brand’s vehicle.

Ambilight EC smart dimming technology leverages its leading-edge capability to mass-produce large-area curved products, precisely matching automotive sunroof designs. As summer approaches, whether navigating city streets or embarking on long journeys, the Ambilight EC smart dimming sunroof not only provides refreshing comfort but also offers an unobstructed view, adding a unique touch of enjoyment to every drive.