Ceramic Window Tinting: Advantages for Sunroofs and Heat Rejection Tips for BMW Owners

Ceramic Window Tinting: Advantages for Sunroofs and Heat Rejection Tips for BMW Owners
Window tinting -- Carbon vs Ceramic ? | BMW i4 Forum

Ceramic tint is a popular choice for window tinting, as it offers excellent protection from infrared (IR) radiation. However, when it comes to sunroofs, the glass itself can block IR radiation, making ceramic tint unnecessary. To verify this, one can use a TV remote and a phone camera; the camera should be able to see the near IR from the remote when the remote ON button is pressed. If the sunroof is placed between the remote and the camera, the camera cannot see anything.

Conventional TV remotes, cameras, etc., use near-infrared (IR-A) radiation for controller transmission (800-2,500 nm - generally around 900-ish nm). These wavelengths generate almost no heat. Solar (thermal) radiation that generates heat ranges from the longest wavelength IR (IR-C - 3,000 nm-ish) through the visible light spectrum to shortwave UV. Near infrared will pass through most glass, but far infrared will be absorbed and generate heat. Most window tint generically blocks IR, UV and visible light, in varying wavelengths, reducing both light and heat.

The electrochromic roof costs $15,000+ to replace if it gets chipped or cracked, which very easily happens from road debris. To protect it from damage, some people might consider putting some PPF on it. According to an article, nearly all the infrared radiation in sunlight is near infrared, shorter than 4 micrometers. It's possible that the glass with PDLC glazing blocks the TV remote wavelength better than the rest of the NIR spectrum.

For folks who did tint their sunroof with ceramic tint, many have reported feeling an improvement in heat rejection. One person living in South FL reported that before tinting, hovering their hand about 1 inch or so from the moonroof (while inside the car), they could feel plenty of heat coming through even under the dark setting. After tinting with 5% ceramic, they reported a 75% improvement in heat rejection.

It's important to note that while ceramic tint does help with heat rejection, much of this improvement may be due to the 5% VLT alone (i.e not the ceramic properties). Depending on climate conditions and personal preference, one may want to opt for a lighter VLT to let more light in during cooler months. Working with a local tinter approved by a BMW dealer is also recommended for best results.

Finally, many have wished BMW had made the opacity adjustable like windows in Boeing 787 instead of just on or off. This would give drivers more control over how much light and heat enters their vehicle at any given time.

In conclusion, ceramic tint is not necessary for sunroofs as the glass itself can block IR radiation. However, if one wishes to improve heat rejection, they may want to consider a lighter VLT and/or working with a local tinter approved by a BMW dealer. It would be great if BMW had made the opacity adjustable like windows in Boeing 787 instead of just on or off.

Does the sunroof glass block near infrared (NIR)?

Yes, when in "opaque mode", the sunroof glass blocks near IR, which is half of solar radiation energy. When in "transparent mode" IR isn't blocked nearly as much.

What type of radiation do conventional TV remotes and cameras use?

Conventional TV remotes, cameras, etc., use near-infrared (IR-A) radiation for controller transmission (800-2,500 nm - generally around 900-ish nm). These wavelengths generate almost no heat.

What is the difference between near infrared and far infrared?

Solar (thermal) radiation that generates heat ranges from the longest wavelength IR (IR-C - 3,000 nm-ish) through the visible light spectrum to shortwave UV. Near infrared will pass through most glass, but far infrared will be absorbed and generate heat.

What is the benefit of window tinting?

Most window tint generically blocks IR, UV and visible light, in varying wavelengths, reducing both light and heat.

Is it necessary to add PPF on BMW's sunroof with PDLC technology?

The electrochromic roof costs $15,000+ to replace if it gets chipped or cracked, which very easily happens from road debris. Adding some PPF on it can help protect it from damage.

Does ceramic tint help with heat rejection?

Yes. Tinting with 5% ceramic makes a huge difference in heat rejection. Depending on your climate, it might be sufficient to keep the cabin comfortable with nothing else.

Is it possible that the glass with PDLC glazing blocks the TV remote wavelength better than the rest of the NIR spectrum?

Yes, it's possible.

Is it advisable to work with a local tinter approved by the local BMW dealer?

Yes, working with a local tinter approved by the local BMW dealer is important. They will have the right tools and materials to ensure a quality job. They will also be able to provide you with a warranty for their work.