What is solar control?

Modern buildings tend to be designed with large amounts of glass making up the façade. As such, some of the concerns with all glass façades are solar control and the comfort of occupants. Solar control is the capacity of glass to manage the amount of solar radiation that enters a building. With increased solar control, the amount of natural daylight, glare and interior temperature of the building can be managed.

Solar transmission loss explained

With proper glazing design and attention to building orientation, the advanced solar control of the glazing may lead to the ability to reduce the size of the air conditioning units.
The benefits of solar control glazing are important in all offices, façades and roof glazing applications. Depending on the glass size and orientation of the wall, solar control glazing can also be effective in residential homes, conservatories and shopfronts.

Selection of Glass Based on the Desired Type of Protection

Light protection

This is necessary when combatting dazzling due to direct exposure to solar radiation. This can be obtained primarily by reducing light transmission by resorting to an absorbent (tinted) glass pane and/or a reflective one (with a metal coating).

Solar protection

The solar energy that passes through a glass pane is converted into heat. By means of combined use of absorbent (tinted) glass panes, reflective ones or low-emissivity ones, it is possible to control solar radiation in the visible and infrared zones.

Protection against UV

Ultraviolet radiation, with its high energy and short wavelengths, can damaging inks, pigments and polymers. This damage can result in discoloration of fabric, clothing and other internal fittings, and it may also bring about the breakdown of unprotected plastics. Visible light can also cause damage, but the main cause of damage to materials arises from the UV radiation wavelengths. The probable effects of damage will increase exponentially hand-in-hand with reduction in wavelength. Saflex interlayer is formulated to provide selective filtration of more than 99% of ultraviolet radiation.

Solar Performance of Laminated Glass

Clear laminated glass

Laminated glass with Saflex interlayer absorbs more than 99% of UV radiation (< 380 nanometres). It also absorbs more infrared radiation than clear monolithic glass of the same thickness. The solar transmission of 33.2 laminated glass is 4% less than that of ordinary 6 mm glass, while its light transmission is only 1% less.


Tinted laminated glass

Utilisation of colored Vanceva® interlayer or tinted glass in the laminated assembly makes it possible to open up wide ranges of wavelengths in the visible range, and to reduce light and solar transmission depending on the color intensity. The tint intensity does not depend on the thickness of the PVB but on the density of pigmentation. In the case of laminated glass panels with colored Vanceva interlayer (also 99% UV protection), the light energy characteristics are shown in the following table.n-hand with reduction in wavelength. Vanceva interlayer is formulated to provide selective filtration of more than 99% of ultraviolet radiation.


Eastman has experience with multiple interlayer products being used in the design of glazing for solar control. 

Although most of the Eastman architectural PVB interlayers can be laminated with coated glass to provide solar control, Saflex Solar is special.  

Saflex Solar is a solar absorbing PVB interlayer that brings improved solar control by reducing solar heat gain versus clear and conventional laminated glass without coatings.  Saflex Solar can also be incorporated into single unit laminated glass with low-emissivity hard coatings or into insulating glass units (IGU) with or without low-emissivity glasses.  Typically used with heat-strengthened or tempered glass, Saflex Solar may be an effective product for reducing solar heat transfer deeper into a building and may aid in the reduction of glare. 

Saflex Solar can be used for:

  • Safety: in case of glass breakage from human or accidental impact, the shards of broken glass will remain adhered to the interlayer providing a reduction in cutting or piercing injuries.  With properly glazed laminated glass in a framing system, fall through protection may also be provided.


  • Storms:  laminated glass with adequate interlayer thickness is capable of thwarting wind-borne debris from penetrating the façade and subsequently allowing destructive internal pressurization in severe windstorms such as tropical cyclones, typhoons and hurricanes.   The ability of the interlayer to contain the glass shards after breakage has been demonstrated to contribute to enhanced glass retention during seismic activities as well. 


  • Security: a laminated glass configuration can be incorporated into a system to provide a sufficient level of protection against man-made intentional attacks, including vandalism and burglary, explosion resistance and ballistic assault.

Combining Saflex® Solar and solar control coatings for optimal performance

Saflex® Solar interlayer is a high visible light transmittance, near infrared (NIR)- and UV-radiation absorbing technology designed to enhance solar heat gain performance, especially when compared to monolithic clear glass and laminates made with conventional clear polyvinyl butyral (PVB) interlayer. When combined with reflective and/or colored glass coatings, it can make for a highly effective solar control solution that is capable of reducing solar heat gain, reducing transmittance of UV radiation and reducing glare.

Saflex Solar PVB can be used to significantly improve the g-value (a.k.a.: solar heat gain coefficient; SHGC) of façades, even if used in combination with robust solar control coatings. Such a solution reduces the transmittance of UV and much of the near-infrared radiation, while allowing optimal visible light transmittance (VLT). While certain coatings can provide the desired reflected color and overall light transmission, the addition of Saflex Solar interlayers improves the luminous efficacy (ratio of light transmittance to the g-value). 


In certain applications, commercial solar control coatings alone may not be sufficient to reduce the g-value to the desired level while keeping an acceptable visible light transmission. Saflex Solar, when combined with these type of coatings, can reduce g-values 0.1 to 0.17unit points further while reducing VLT by only 5-- 10%. 


Combining solar interlayers with coatings has been done for decades. Validation of compatibility for individual coating types should be approved by the coating manufacturer.  Variables such as glass type choice, permanence of adhesion, and other durability characteristics should be considered when assessing overall performance. For example, solar PVB does not contribute significantly to solar performance in insulating glass units where high performance selective solar control coatings are used. 


The use of Saflex Solar can also be effective with low-e pyrolytic coatings.  This is an effective tool in laminated glass design especially in regions where advanced solar control coatings may not be widely available. In addition, Saflex Solar interlayers are ideal for curved glass applications, where low-reflectance is desired and when a consistent reflected color at angle is required of the glazing.


Choosing the right Saflex Solar combination provides several options, please contact your regional representative for assistance or more details.


Can laminated glass affect the health of plants?

Laminated glass is recommended and used for greenhouses and botanical gardens.

In fact, the photoreceptors of plants absorb solar energy in certain ranges of the visible scale (mainly around 450, 660 and 730 nanometres). Thus, laminated glass enables passage of all of the energy required for photosynthesis in plants. It may make it possible to protect the color and reproduction of flowers from the unwanted effects of UV radiation. UV radiation is also a calcium-absorption factor, which makes leaves fragile and apt to break. In the case of a few rare species, however, input of UV radiation is helpful to the development of colors and for production of anti-UV pigments. For these specific cases, it is appropriate to consult a specialist in horticultural matters in-hand with reduction in wavelength. Saflex interlayer is formulated to provide selective filtration of more than 99% of ultraviolet radiation.

Which products fit in?

Saflex Solar is a solar absorbing PVB interlayer specially developed to improve the solar control.  Compared with standard clear polyvinyl butyral (PVB), it can decrease solar heat gain through the glazing while having a high visible light transmittance.
Furthermore, Saflex Solar provides safety, security and acoustic performances similar to conventional Saflex Clear PVB interlayer. 

Combinable with other Saflex PVB interlayers

Saflex Solar can be combined with:

  • Saflex Clear, the conventional PVB interlayer.

  • Saflex Acoustic, an engineered tri-layer interlayer that provides enhanced sound damping between 1000 – 4000 Hertz (Hz) as compared to conventional PVB interlayer.   The enhanced performance may allow the glazing construction to be designed using less air space and/or thinner glass to achieve the same sound reduction rating versus conventional and historic practices. 

  • Saflex Structural PVB interlayer can be used in laminated glass configurations targeted for floors, stairs, fins, balustrades, guards and canopies.

  • Saflex High Protection (HP) and Saflex Storm interlayers can be used when enhanced protection from tropical cyclones, typhoons and hurricane force winds with windborne debris are needed.

  • Vanceva® Earth Tones collection and Vanceva Colors interlayers bring forth the possibility of using a large range of color in a façade or as interior glazing without having to increase glass thickness to achieve color intensity, be delayed waiting for colored glass campaigns or ordering large quantities of custom colored glass.  Both products provide the flexibility to customize or modify and improve the aesthetic of the façade and aid in the reduction of glare.  Saflex Solar can contribute to a color shift when combined with Vanceva Colors or Earth Tones.  A sample and mock-up panel should always be requested and reviewed prior to specification.

Since the various types of Saflex and Vanceva interlayers mentioned above can be combined between two pieces of glass or in the same glazing configuration, the overall performance of the glazing system can contribute to the optimum performance of the façade.

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