Tinted glass is a great strategy for limiting solar heat gain, reducing glare, lowering heating and cooling loads and enhancing occupant comfort.
While still enabling daylighting and views, tinted glass also limits the ability of passersby to peer inside. That’s why it’s commonly used to provide privacy in applications like healthcare, education and corporate settings.
It has taken several decades of developing and refining technologies to reach the current level of performance and aesthetics. Today’s tinted glass products deliver great solar heat gain protection, visibility and longevity, and are predominantly available in blue, green, bronze and gray.
The first attempt at tinting came in the form of metallic spray-on coatings. While this method provided some tinting, it was difficult to install evenly and often resulted in streaking.
The first commercially viable window film was brought to the market in 1966 by 3M. This dye-based polyester film was adhered to a pane of glass and provided color and solar control. Marking the beginning of the modern window film industry, this enabled tints for buildings and automobiles and was considered a significant breakthrough. However, the technology had limitations. The film absorbed high levels of heat, causing the dyes to break down, eventually leading to discoloration and bubbling.
The energy crisis of the 1970s then drove demand for tinted films to help contribute to energy efficiency in buildings. To improve durability and performance, scratch-resistant coatings were developed. By applying a thin, clear layer of resin made from acrylic or polyurethane to the film’s outer surface, these coatings extended the life of the film.
But still, the sun’s rays continued to degrade the film and weaken its adhesion to the glass. Through R&D of bonding agents, this led to improved pressure-sensitive adhesives which also delivered better shear strength and thermal stability.
The next technological advancement came in the form of metallization, which greatly improved the film’s ability to reject heat. This involved vacuum-coating and sputtering processes to deposit ultra-thin layers of metals – for example, aluminum or nickel-chromium alloys – onto the film. This ability to reflect infrared radiation offered a more efficient solar control strategy and became the go-to solution in the 1980s and 1990s.
Still, there were some shortcomings, namely high reflectivity that created a mirror-like appearance and interference with electrical signals. Due to the metallic content, the film acted as a radio frequency shield and created issues with GPS, cell phone reception and satellite radio signals.
Brown & Brown Headquarters, Daytona Beach, FL
Products: Solarblue® Glass, Solarban® R100 Glass
Architect: Reynolds, Smith & Hills
Glass Fabricator: Tristar Glass Inc.
Glazing Contractor: West Tampa Glass
Photographer: Tom Kessler
More recently, a combination of nanotechnology and ceramic tints has provided superior heat reduction without compromising GPS, cell phone reception and signal clarity.
Special inorganic nanoparticles, such as titanium nitride or tungsten oxide, are engineered to selectively filter out the sun’s infrared radiation. Because ceramic materials are nonmetallic, there is no issue with radio frequency interference.
Another strategy is body-tinted glass which uses metal oxides dissolved into the glass melt instead of metallic layers. Because the metal oxides are dispersed at the atomic level, they are non-conductive and therefore don’t interfere with radio waves.
For example, Solarblue® sky-blue tinted glass and Optigray® light-gray tinted glass combine solar control, light transmission, low reflectivity and strong aesthetic appeal.
Another newer technology is spectrally selective glass.
This technology filters specific components of sunlight, thereby reducing heat while preserving optical clarity. Specifically, all infrared heat and most of the ultraviolet rays are blocked while the visible light passes through.
3Eleven, Chicago, IL
Products: Solarban® 60 Optigray® Glass, Solarban® 60 Clear Glass
Architect: FitzGerald
Glass Fabricator: Oldcastle BuildingEnvelope®
Glazing Contractor: CK2
Photographer: Tom Kessler
Examples include emerald-green Atlantica® glass and light green Solexia® glass by Vitro Glass.
Both the full-body-tinted and spectrally selective glass options can be paired with Solarban® solar control low-e glasses to deliver higher levels of solar control and light transmittance.
Though more of a niche market, another way to tint glass is through smart windows, also known as electrochromic glass. In this case, liquid crystals are sandwiched in between two layers of film. When activated by electricity, the windows change from clear to dark and vice versa. Consequently, depending on the sun’s intensity and/or occupant needs, users can easily switch back and forth with the flip of a switch.
In addition to providing privacy and performance, architects often specify tinted glass to better blend with a building’s interiors and/or surrounding environment, as well as create a certain ambiance or reflect a company’s brand.
To create a desired tint, specific metal oxides are added to the mix of standard ingredients that constitute glass, namely silica sand, soda ash, dolomite and limestone, which are dissolved in a furnace. To create green, iron oxide is added; for bronze, it’s selenium; and gray or blue can be created with combinations of cobalt and nickel.
A bronze tint like Solarbronze® glass is a great way to complement brick, stone or wood facades and interiors. The tint lends a soft, warm appearance and works well with the growing prominence of natural hues in contemporary architectural color palettes.
Blue tints like rich-blue Pacifica® glass are the traditional choice for corporate, high-tech, industrial and healthcare settings. When used near water or sky-dominated environments, the crisp, cool blue tints can invoke a sense of calm, clarity and innovation.
United Neighborhood Organization (UNO) Veterans Memorial Campus at Archer Heights, Chicago, IL
Products: Solarban® 60 Atlantica® Glass, Solarban® 60 Solexia® Glass, Solarban® 60 Pacifica® Glass, Solarban® 60 Clear Glass
Architect: UrbanWorks, Ltd., Glass Fabricator: TRACO, Glazing Contractor: Auburn Corporation, Owner/Developer: United Neighborhood Organization (UNO) Charter School Network, General Contractor: F.H. Paschen/DENCO Construction Management
Meanwhile, gray tints such as Solargray® glass are selected when a building design is seeking a sense of neutrality, balance and professionalism. Gray tints can help reduce the sun’s brightness while preserving the true colors of the landscape.
Another way manufacturers can introduce color to glass is through reflective glass. This type of glass is produced by manipulating the application of magnetron-sputtered vacuum deposition (MSVD) coatings on solar control low-e glass. Reflective glass offers higher levels of thermal performance and can be paired with tinted glass to produce a bolder tint.
For example, the mid-reflective Solarban® R77 glass presents a cool silver-blue aesthetic and Solarban Champane™ glass delivers a warm, golden champagne color. Solarban Champane™ glass also can be coated on tinted glass options like Optigray® glass and Solarbronze® glass to enhance these gray and bronze colors and deliver high energy efficiencies.
To learn more on high-performance tinted glass, visit Vitro’s Tinted Glass page.