Adaptable Glazing Shields



Photo of Anas Al Kassas

Anas Al Kassas

Founder & CEO at Inovues




Today, about 40% of all buildings in the U.S. still have single-pane windows, and ~70% of the existing building stock is estimated to suffer from under-performing facades. Experts project that 20-40% of the total energy savings in buildings—the #1 end users of energy—to be from windows and building envelopes. Thus, the demand for energy-efficiency facade and window retrofits/upgrades is estimated to grow rapidly over the coming years due to the rapid adoption of energy-efficiency regulations for existing buildings, which in turn, are influencing the real-estate market.

The problem is that window replacement is a highly intrusive and costly solution that is often carried out only when the windows reach the end of their service-life and must be replaced. Additionally, most glazing systems—including the current ones—are designed with little consideration (if any) given to their inevitable retrofit during the service-life of the building. Thus, most facade and window retrofit practices are often considered not feasible as well due to the associated complexity, building and business disruption, and long payback period.

This paper presents the concept of Inovues’ patent-pending, external window upgrade system and non-intrusive facade retrofit method. The technology provides a cost-effective and sustainable solution for upgrading the old/inefficient, single- or double-glazed curtainwalls to high-performing double- or triple-glazed systems without requiring any replacement or causing building or business disruption. A case study using Lever House in NYC is presented, which is one of several performed to analyze the visual impact, thermal performance, payback, and ROI. The results showed an improvement of over 50% in the total system U-Factor; over 250% increase in condensation resistance; ~15% improvement in thermal comfort in the perimeter areas; nearly 20% energy savings; and ~85% shorter payback period (compared to replacement) with ~300% ROI over the estimated 20-25-year service-life of the system.


In the United States—the second largest energy consumer and greenhouse gas emitter in the world after China—most GHG emissions come from energy consumption and production (84% in 2014), and carbon

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Despite the steady and fast growth over the past few years and the projected increase in demand in the future, the building envelope energy-efficiency market is still considered a largely

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Adaptable Glazing Shields

An external window-upgrade system “glazing shield” and a non-intrusive facade retrofit method are being developed. The objective is to provide a cost-effect and sustainable solution for upgrading the inefficient single-

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Several before-and-after system-based and building-based analysis studies were performed on different glazing systems and existing buildings to analyze the overall impact and feasibility of the glazing shields. This includes visual

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Lever House - Case Study

Key Attributes

Designed by Gordon Bunshaft of SOM and built in 1952 (Fig. 5).2nd curtainwall building in New York City.Designated as a New York City landmark in 1982 and was

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Figure 12: Thermal simulations at the horizontal meeting rail of Case 1 system showing the impact of each intervention scenario on the frame and edge of the glass U-Factor. Image

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Summary of the System-Based Simulation Results at Lever House

Opt 1 improved the thermal transmittance (U-Factor) of the curtainwall system by 53.4% and the condensation resistance (CR) by 238.5%.Opt 1a

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Conclusion and Future Work

The purpose of this paper is to present the concept of a patent-pending, external window upgrade system and non-intrusive facade retrofit method. The technology would work with most types of

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Rights and Permissions

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