From windows that change opacity with the touch of a button to “solar panel” glass, these incredible innovations seem more like they come from a Syfy channel than from real life.
As a result, it’s important for new entrants to provide technologies that can be easily adopted by window manufacturers. This will help reduce costs and time to market, while ensuring that building owners and homeowners can reap the benefits.
Double glazing
Windows have come a long way from the single-pane, poorly insulated models of decades past. Today, double-glazed windows are the standard for energy efficiency in most climates thanks to an insulating space between the panes that can be filled with air or noble gases such as argon and krypton. These insulating gaps also help reduce noise transmission and condensation.
Tried and true low-emissivity (Low-E) coatings are also seeing innovation as startups develop new approaches that offer even lower infrared heat reflection to maintain indoor temperatures and keep out outdoor cold and sun. Additionally, the spacer bars that separate the window panes are being made from materials with a better thermal rating and integrated desiccants to mitigate moisture buildup.
Ultimately, double glazing innovations will help to dramatically reduce energy consumption and greenhouse gas emissions, saving building owners on utility costs over the long term. In addition, many of the materials used in these advanced systems can be recycled or repurposed, furthering sustainability and contributing to a circular economy where resources are endlessly reused and renewed. Lastly, policies and regulations that support double glazing innovations are essential to driving market adoption. These include government incentives and subsidies, energy efficiency standards and building codes, and initiatives that encourage industry collaboration and partnerships. With the right framework in place, these technologies can be rolled out at scale to drive a massive reduction of global energy consumption and carbon footprints.
Inert gas fills
Modern double and triple glazed windows feature a space between the panes that is filled with inert gases, such as argon or krypton. These noble gasses are denser than air and help reduce conductive and convective heat transfer through the window. They also block outside noise and provide additional insulation.
The best option is argon, which is colorless, odorless, non-toxic and common to the atmosphere (the Earth has less than 1% argon), making it cheap and easy to produce. It performs 67% better than air in a standard double-pane insulated glass unit (IG) and works well in larger gaps like those in most newer windows.
Krypton is another popular choice, offering slightly better performance than argon in the same space and performing well in most double and triple-pane IGs. It’s usually more expensive than argon, however. It can be mixed with argon and other gases such as xenon to give better performance at a lower cost.
Other innovations that improve the energy-related properties of windows include aerogel glazing which eliminates the need for inert gas fills and Low-E coating, and vacuum IG units that use a silica-based solid between glass panes to greatly enhance their insulating properties. These advances make it possible to build ultra-thin IGs that have more energy-related benefits than older windows, but are still affordable and aesthetically pleasing.
Smart glass
If you want your windows to adapt to the weather, match your mood, or give you privacy year-round, high-tech smart glass may be the way to go. But these window innovations often come with steep price tags. That could be due to complicated power systems or lengthy installation processes. Or, in the case of electrochromic windows, a significant amount of energy is used to change their state, which can raise costs.
Scientists are working to lower the cost of smart windows by improving the materials they use. For example, a team led by Yi Li of the University of California at Berkeley developed a two-way window that transitions from clear to tint when the window’s temperature changes. When it’s hot, the window automatically enters a haze state that blocks heat-packed infrared light and keeps rooms cool. In winter, the window enters a transparent state that lets in warm natural light without losing energy efficiency.
Other scientists are developing new smart glass technologies that can respond to different prompts, such as temperature and light. For instance, one approach uses a layer of tungsten oxide between a glass pane and a film that can be activated by small jolts of electricity to alter how the material interacts with light. Another smart glass solution employs a diarylethene dye incorporated into liquid crystals, which reacts to specific wavelengths of sunlight and electrical triggers to control transparency.
Sustainable materials
Aside from reducing energy costs, many innovations in window technology are designed to protect our environment and wildlife. For example, new bird-friendly windows are patterned with dots that make it more difficult for birds to fly into them. They also reflect the sun’s rays, which would otherwise burn birds’ wings.
Another innovation that could save energy is transparent solar glass, which combines photovoltaic (PV) cells with traditional window glass to generate electricity without affecting transparency. The PV glass is a thin layer that collects sunlight and converts it to energy through crystalline solar cell coatings. The solar energy is then stored in a battery or fed to a building’s electrical grid, enabling it to offset some of the energy it uses.
One of the most important advances in window technology has been the development of low-emissivity (Low-E) glass. This special coating prevents heat-packed infrared radiation from entering buildings during the summer, thereby cooling them. It also helps block interior heat from escaping during the winter, saving energy.
Other innovative materials being developed for smart windows include gaschromic glazing, which turns from clear to tinted automatically when temperatures change. This is especially useful in climates like ours, where seasonal changes can cause dramatic fluctuations in temperature. These technologies are being marketed to window manufacturers that manage final assembly and sale, which allows them to reach economies of scale more quickly.