Clear Channel Outdoor Chicago Office Low-E Window Film, 2022

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Location: Chicago, Illinois

The Challenge

Project at a glance

  • Client: Clear Channel Outdoor, Chicago office
  • Year: 2022
  • Glass: 1/4 inch single pane clear glass in occupied office space
  • Problem: cold glass in winter
  • Film: Solar Gard Ecolux 70 Low-E window film, about 1,200 square feet, applied to the inside of the glass
  • Edge seal: DOWSIL 995 silicone around the edge of the film
  • Schedule: installed in sections to keep disruption to a minimum
  • Result: an immediate improvement in heat retention, and positive comments from staff almost right away

The office windows are 1/4 inch single pane glass, and in winter the glass was cold and staff near the windows felt it. Single pane glass loses heat quickly: Solar Gard lists 1/4 inch single clear glass with no film at a winter U-factor of 1.02. Clear Channel Outdoor wanted the offices more comfortable without replacing the windows.

The Solution

In 2022 AAA Glass Tint installed Solar Gard Ecolux 70 Low-E window film on about 1,200 square feet of the office’s single pane glass. Low-E film has a thin metallic coating with low emissivity, so it reflects room heat back into the space instead of letting the glass give it off to the outdoors.

Solar Gard’s published figures for Ecolux 70 on 1/4 inch single pane clear glass, calculated with NFRC methodology:

  • Winter U-factor: 0.60, against 1.02 for the same glass without film (lower means less heat lost through the glass)
  • Emissivity: 0.09, against about 0.84 for clear glass
  • Visible light transmitted: 67 percent, so the offices keep their daylight and view
  • Visible light reflected outside: 13 percent, so the glass does not look mirrored
  • Total solar energy rejected: 53 percent, which also helps in summer

Our crew sealed the edge of the film with DOWSIL 995 silicone. Along with sealing the film edge, the new bead closed air gaps in the existing caulking. We worked in sections so the office kept running. We do not subcontract installation; our own crews do the work.

The Result

The improvement in heat retention was immediate, and staff made positive comments almost right away. The windows stayed in place, and the offices kept their daylight and view out.

Conclusion

Questions about this project

Does Low-E window film help with cold single pane windows? Yes. On 1/4 inch single pane clear glass, Solar Gard lists Ecolux 70 at a winter U-factor of 0.60, against 1.02 with no film. A U.S. General Services Administration study of room-side Low-E film on single pane windows, using a film from a different manufacturer, found it nearly doubled the insulating performance of the windows. We look at what that means for energy use in the Chicago climate in How Much Energy Does Commercial Window Film Save?

Is Low-E film a replacement for new windows? Not always. Film improves the glass; it does not fix failed seals, rotted frames or air leaks through the frame. We compare the two in Low-E Window Film vs. Window Replacement.

Does Low-E film darken an office? Very little. Ecolux 70 transmits 67 percent of visible light on 1/4 inch clear glass. We explain U-factor and emissivity in our window film performance terms guide.

Can it be installed while the office is open? Yes. On this project we worked in sections to keep disruption to a minimum. After-hours and weekend installation is available at additional cost.

See our Low-E window film service, or request a free assessment.

For more of our work in Chicago, see commercial window film in Chicago.

Sources: Solar Gard, Ecolux 70 Low-E film, Section 08 87 13 specification 04/25 (U-factor, light and solar figures) and data sheet PDF0314ECX70 04/13 (emissivity); Solar Gard, Panorama data sheet SK0314PANSL2 09/20 (U-factor of 1/4 inch single clear glass without film); U.S. General Services Administration, Green Proving Ground, GPG-032, 2017. Ecolux 70 is listed in the NFRC Certified Products Directory as product SGF-K-049 (reviewed October 11, 2026). Figures are manufacturer ratings on the glass named; results on other glass differ. Reviewed by David Johnson, owner of AAA Glass Tint. Last updated October 19, 2026.

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