Privacy glass vs Aftermarket tint

A common misconception with the purchase of a new car is that the “tinted” windows will provide you and your car’s interior from damaging UV rays.


Most car manufacturers install what is known as "privacy glass "... this will not provide you with UV protection or even heat rejection.

 “privacy glass ” will not provide you with UV protection or even heat rejection.

This glass is typically dyed glass and provides only privacy.  Solar glass is a step up from the clear automotive glass and has visible light transmission (VLT) varying from as low as the federal limit of 70% VLT up to 88% VLT (which is clear auto glass). Most automotive solar glass ranges 74-84% these days with UV rejection not much over 40% unless it is factory privacy glass, which has UV rejection as high as the 60 percentile range. Some cars, trucks and sport utility vehicles, in particular, come from the manufacturer with glass that has been darkened using an electrical process called “deep dipping”. This “factory tinted” glass is a dark shade but does not protect the interior of your car from the sun’s heat or damaging UV rays as well as aftermarket window tinting. Major film manufacturers have formulated tinting materials to closely match the factory tinted glass allowing the front door windows of some truck and SUVs have window tint with a legal matching shade. It is also possible to apply aftermarket window tinting over factory tinted glass to make the windows darker and to improve performance.

In other words, “factory tint” means the dye is actually in the glass, it can never be removed. “Aftermarket tint” is a transparent paper with an adhesive side that bonds to the glass, it can be removed.

“When you apply a low visible light transmitted [or VLT] film to an already dark window, such as on an SUV, you’re creating not only the privacy effect, but you’re giving yourself all of the benefits of the thermal barrier for heat rejection and heat absorption, “says Tony Scire of 3M Auto Care Market Center. “It’s very important to understand that eve

n though the glass looks dark coming out of the factory, there are no thermal performance characteristics in the glass.”

Josh Buis of Window Film Operations for Scorpion Window Films agrees that while factory glass may look similar to windows that have aftermarket films installed on them, the performance is rarely up to par with the aftermarket.

“There are many vehicle manufacturers that provide tinted windows from the factory, but this is nothing more than privacy glass and offers to vary little protection from the sun and all of its damaging properties,” he says. “The addition of a light VLT film over your OEM privacy glass will increase the protection on the interior in the rear of your vehicle.”

All of which is to say that when it comes to protection, most OEM window treatments are generally focused only on aesthetics, not performance. That becomes a key selling point for restylers as they educate their customers.

Aftermarket films, however, provide a host of other benefits beyond mere appearance, says Ari Sacal of Solar Gard.

“In North America, 90% of side and rear car windows manufactured today offer very minimal protection from UVA rays,” Sacal says, noting that aftermarket films can block up to 99% of UVA and UVB. “[Aftermarket products shield] passengers against premature aging and skin cancer, and discoloration or fading of leather, vinyl, and fabric … and protect a customer’s investment in their vehicle by protecting passengers and the vehicle interior from UV rays, enhancing passenger comfort and customizing the vehicles aesthetic appearance. This shield protects the passenger’s skin from the sun’s damaging rays, regardless of the film darkness.

“Window films also reject solar energy, decreasing a vehicle’s interior temperature, reducing the need for air conditioning and cutting glare,” he adds.

Block Heat and UV Rays without dark tint

Crystalline line reject 99.9 percent of UV radiation and 90 to 97 percent of infrared radiation.


MOTORTREND Article on Crystalline Automotive Films

A few weeks ago, 3M invited us out for a demonstration of its automotive products. Aside from being an excuse to get of the office, the event offered us an in-depth look at some of 3M’s lesser-known products. While all of the products demonstrated served to enhance a car’s appearance, each had a practical application as well. For example, 3M’s vinyl wraps serve as a removable protective coating for your car’s paint, while also lending it a distinctive look. The Headlight Lens Restoration

The Headlight Lens Restoration System, while capable of bringing yellowing plastic headlight housings back to near-original condition, also restore light output to more acceptable levels.

But of all of 3M’s offerings on display that day, the one that piqued our interest most was the company’s Crystalline line of automotive window films. While window tint is nothing new, 3M’s Crystalline films are several shades lighter than your average window tint — almost clear, in fact — and are claimed to reflect just as much energy if not more. According to Jon Hanbury, Marketing Manager for 3M’s Renewable Energy Division, clear window films were developed mostly for drivers who wanted the benefits of tinting without having to darken their windows, which could potentially reduce visibility at night. State laws regarding window tinting were also a factor since many states outlaw anything with less than 50% VLT (Visible Light Transmission). In other words, 3M wanted to offer a film that would allow light in, but keep heat and UV radiation out.

Although it’s been on the market for about four years now, 3M’s clear window films haven’t gotten much attention from the automotive press. While perhaps not as exciting innovation as something like an eight-speed transmission, the development of a clear window film such as this is significant nonetheless. To better demonstrate the film’s ability to reject heat, 3M had a table set up with small halogen lamps, each with several glass slides that could be inserted in front of the lamp’s beam. Each slide was laminated with a different film, with one left uncovered as a control. Waving your hand over the plain glass slide, you could feel the lamp’s heat passing through virtually unimpeded. When you inserted the slide with the traditional tint applied, there was a noticeable decrease in the heat radiating from the lamp. The 3M clear film slide, which didn’t look that much darker than the plain glass, seemed to reduce heat even further. While this demonstration impressed us on the basis of feel, it didn’t tell us exactly how effective the films were.

For that, 3M’s technicians were on hand to answer questions regarding the Crystalline series’ performance. According to 3M, the company’s clear films will allow anywhere from 40 percent to 90 percent of visible light into a car, depending on which grade is chosen. Also dependent upon which grade is chosen is the amount of solar energy rejected, which ranges from 34 percent to 60 percent. To put that into perspective, the darkest conventional tint 3M offers only rejects 45 percent of solar energy while allowing only 6 percent of visible light in. Although the amount of light and heat let in varies, 3M claims that all films in the Crystalline line reject 99.9 percent of UV radiation and 90 to 97 percent of infrared radiation. Because these films significantly reduce exposure to UV rays, they are recommended by the Skin Cancer Foundation as an effective defense against ultraviolet radiation — which it identifies as a leading cause of skin cancer.

Reducing the heat allowed into a car’s interior by 60 percent could mean the difference between being greeted by a bearably warm seat or burning your hand on the gear selector. It’s conceivable, then, that a cabin that doesn’t get as hot wouldn’t need to run the air conditioning as frequently or as high. If the AC system doesn’t have to work as hard, then the engine doesn’t have to work as hard. While it’s true that reducing AC usage would improve fuel economy, 3M currently has no data on just how much. However, 3M’s Jon Hanbury says that quantitative fuel economy testing may be taking place at one of the company’s international facilities.

Anyone that does a lot of driving — for work or otherwise — can likely appreciate cooler interior temperatures and not having to wear sunscreen in the car. With costs ranging from $500 to 800, installation of 3M’s window films isn’t exactly cheap. But if the films deliver all the benefits listed above and can also be proven to get better fuel mileage, it just might justify the cost. In an age where the national average price for gas is creeping up on four dollars per gallon, every little bit counts.

Protection for your home and your health


To see the damage that untreated glass can do, take a close look at the furnishings in your home.

While it’s understood that taking sun safety precautions is important outside, few people realize they can sustain sun damage indoors, too. While both ultraviolet A (UVA) and ultraviolet B (UVB) radiation from the sun can harm the skin and lead to skin cancers, UVB is effectively blocked by glass. However, at least 50 percent of UVA rays can pass through windows. Window film is an increasingly effective solution, offering substantial indoor protection by blocking up to 99.9 percent of UVA radiation.

Although they are less intense than UVB, UVA rays are 30 to 50 times more prevalent and are present with relatively equal intensity during all daylight hours throughout the year. Window film can help prevent harmful UVA rays from damaging both your skin and your belongings. “To see the damage that untreated glass can do, take a close look at the furnishings in your home that are hit by direct sunlight,” says Perry Robins, MD, President of The Skin Cancer Foundation. “If the sun has faded the color of your sofa, it can just as easily damage your skin when you sit there.”

Available in varied tints, residential and commercial window films can also cut down glare by more than half while allowing 30-80 percent of visible light to get through, depending on the customer’s needs. The benefits of installing window film go beyond protecting one’s skin and household items, as it also can reduce energy costs. In hot weather, window film cuts down heat within the home and in cold weather it reflects interior heat back into the home. Additionally, some new types of “safety” film help hold residential and commercial glass in place if shattered. Several times thicker than the standard sun-protective film, it can greatly reduce the chances of break-ins, property damage, and even personal injury that can result from broken glass.

About 85 percent of melanomas and 90 percent of nonmelanoma skin cancers are associated with exposure to UV radiation. The Skin Cancer Foundation recommends that everyone adopt a complete year-round sun protection regimenthat includes seeking shade, covering up with clothing, wearing a broad-brimmed hat and UV-blocking sunglasses, and using broad spectrum sunscreen every day.

The Skin Cancer Foundation has awarded its Seal of Recommendation to window films manufactured by several different brands, including 3M and Solutia Performance Films. Products granted the Seal of Recommendation have been proven to provide safe and effective UV radiation protection. Use the Seal of Recommendation Product Finder to view products that have earned the Seal.