Building with Dynamic Glass

Written By Matt Chester

Originally posted here.

A View of Efficiency: How Smart Windows Are Transforming Building Energy Use

Current Problem

The rapid and accelerating urbanization of communities across the world comes with an inherent increase to power demand. While bringing modern technologies and buildings to wider populations is a positive trend, the challenge comes from adding to the fact that already 40% of global energy consumption and 27% of global emissions are tied to building operations. Basic building functions, notably heating/cooling (or HVAC) systems and lighting cannot be sacrificed, while an increasingly warming climate is making those HVAC needs even more intense.

To stop that feedback loop of hotter temperatures leading to more building energy use that then leads to more climate-warming emissions, many global thought leaders are identifying how excess building energy use can be curbed. The building envelope is a key area to hone in on, specifically how heat can so easily escape through a building’s windows.

While a rapidly expanding base of large buildings, notably skyscrapers with exteriors covered in glass, brings more energy requirements to the sector, securing the building envelope to ensure excess solar heat gain in the summer and unwanted heat loss in the winter has come into the spotlight. Rather than leaning further into conventional (and ineffective) methods like shades and treated glasses, an emerging technology is bringing dynamic opportunities to best-fit buildings’ needs.

 

Emerging Solution

Specifically, dynamic glass, also called smart windows, can respond to the changing position of the sun and the ever-changing weather patterns to adjust their transparency and tint in response. In doing so, smart windows can be not only energy efficient but also aesthetically optimal. Smart windows, sometimes also called dynamic or switchable glazing windows, represent the next generation in window technology.

Smart windows can change their light transmittance properties based on certain conditions, either automatically (e.g., by position of the sun or the minute-by-minute changes in cloud cover) or by direct user input and preferences. These changing properties are accomplished with multiple different possible technologies, including electrochromic, thermochromic, and photochromic methods. Regardless of the specifics, though, the end result is that the smart windows can transition from clear to partially tinted to fully tinted, allowing control over the amount of sunlight and heat that enters and leaves a space. And with the rise of smart building solutions (such as smart thermostats, voice assistants, and building automation systems), such smart windows can seamlessly integrate into the system-wide energy tracking and optimization.

Initially popular in corporate office spaces to optimize light, improve employee comfort, and minimize whole building energy costs, their application has more recently expanded to residential homes and other commercial areas such as healthcare facilities. By managing daylight and reducing heat ingress, buildings can save significantly on cooling, heating, and lighting costs. This opportunity not only translates to financial savings but also reduces a building’s carbon footprint, an area of increasing attention regardless of sector. Beyond energy savings, smart windows also serve to enhance occupant comfort by reducing glare and maintaining optimal natural lighting levels. Looking ahead, even more advanced solutions have begun to become possible, including windows that can generate energy through integrated solar cells.


Emerging Solutions

LOS ANGELES

Across the vast built environment of the Los Angeles metropolitan area, smart windows have received notable public support as well as specific project implementations that can be held up as examples. From the Los Angeles Green New Deal in 2019 which included a pillar of energy efficiency to the Los Angles Better Buildings Challenge that aimed to reduce building energy use by 22% by 2025, the opportunity for smart windows has been ever-present.  Beyond those targets, action is being found driven by Los Angeles Department of Water and Power (LADWP) as they offer broad residential energy efficiency equipment rebates, with windows being one of the eligible areas.


CALIFORNIA

Looking more widely at the state of California, state code under Title 24 Part 6 (the California Energy Code) sets state-wide energy efficiency standards for buildings. Given the sunny nature of so many major metropolitan centers in California, smart windows have become an area of this code increasingly in focus, with a 2017 update to the California Energy Code explicitly laying out the eligibility of smart windows as a way to achieve mandated efficiency savings, noting that they “provide a variety of benefits, including reduced energy costs due to controlled daylighting and unwanted heat gain or heat loss. While still a relatively new technology, high-performance windows are expected to grow substantially in the coming years.”

Going beyond the mandatory requirements, the California Green Building Standards Code (otherwise known as CalGreen) spells out requirements for sustainable building practices required in all new buildings in California. As with the more general code, CalGreen includes window efficiency as a core component of the building envelope, and some key examples of smart window implementation as a result across California include the following:


NATIONAL

While building codes tend to focus on the more local and state areas, since geographical variations require different considerations, across the country the U.S. Green Building Council’s LEED Certification remains quite influential. Specifically, USGBC’s Leadership in Energy and Environmental Design (LEED) program has been pivotal in the adoption of smart building technologies. As such, USGBC has studied and promoted the use of smart glass technology, with implementation qualifying for 8 LEED certification credits.

Similarly, the U.S. Department of Energy (DOE) launched the Better Buildings Challenge with the aim to reduce building profile energy use by 20% or more, also tapping into the use of smart windows as a cutting edge tool to do so.

From these and other efforts, smart windows have been effectively integrated in some high-profile buildings across the United States:

  • Sven Tower in Queens, New York, the tallest residential building with smart windows in North America

  • The ‘Glass House’ at Middle Tennessee State University, the largest smart window installation at a U.S. college or university

  • Johns Terminal, where 400 feet of floor-to-ceiling smart windows offer clear Hudson River views while allowing the building to be labeled one of New York City’s cleanest and most sustainable.


GLOBAL

The global market for smart windows has seen substantial growth across different sectors and geographies, with various countries and companies showcasing flagship implementations. Some of the most notable international examples of smart window deployment include the following:

  • The Edge, Amsterdam, Netherlands: Often cited as the world’s greenest and most intelligent office building, the Edge in Amsterdam features advanced daylighting strategies supported by smart windows that help control solar gain and maximize natural light.

  • One Albert Quay, Cork, Ireland: Touted as Ireland’s smartest building, One Albert Quay integrates various smart technologies, including smart windows, to enhance energy efficiency.

  • Eureka Tower, Melbourne, Australia: While primarily known for its striking design, the Eureka Tower also incorporates advanced glazing technologies achieved via spray-on methods for even more affordable deployment.

Matt Chester
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