Smart Windows: What You Need to Know
Windows are incredibly important in the design of a home. They are important for the home’s aesthetics, they allow exterior light to enter the home, can be opened for ventilation, and solar energy entering through southern facing windows can help offset home heating costs in the winter. On the down side, according to the U.S Department of Energy, older, inefficient windows can be responsible for over 25 percent of energy costs of heating/cooling a home. For these reasons and more, many homeowners are opting for smart windows.
Windows, like everything else, don’t last forever. The average lifespan of a window is around 20 years. This means there are many homes that could benefit from replacement of windows. The down side of this is that replacing windows isn’t cheap. According to Home Advisor, the cost of replacing windows in an average U.S. home is between $3,000 and $10,000. The good news is that there are some unique technological options available in new windows.
Smart Window Options
If you are replacing your windows, or building a new home where you have input on the windows being used, there are high tech options you may want to consider.
Low-emissivity (low-E) glass has a microscopic layer of metallic particles adhered to the glass. These particles reflect infrared radiation so solar energy from the sun is reflected back, keeping a home cooler in the summer. The coating also reflects infrared radiation within a home helping to keep it warmer in the winter. In addition, the coating blocks UV rays, protecting furnishings within a home from damage from sunlight.
Dual Action Self Cleaning Glass: It seems like magic but there is now a coating that keeps your windows clean. The first part of the coating uses titanium dioxide which combines with sunlight to break down organic compounds (dirt) that have stuck to the glass. The second part of the coating allows water to easily rinse the broken down dirt off the windows.
Window treatments (drapes, shades, etc.) are also expensive; whether you buy them yourself or with the help of an interior designer. If you want to automate your window treatments with motorized models, the cost-per-window can rise to well over $1,000 depending on the fabrics you choose and the quality of the motor (today the higher quality motors are nearly silent).
Smart Window Film
An alternative are smart window films. While this might not be the best aesthetic choice for a classic Victorian home, smart window films remove the need for window treatments by using a window film that can be adjusted from clear to fully opaque through the application of a voltage to the film. The most common technology for smart window films is PDLC (Particle Displaced Liquid Crystal) where a voltage applied to the film causes it to be clear. When the voltage is removed the film becomes opaque. By varying the voltage the amount of opacity can be infinitely adjusted.
The good news for consumers and smart home integrators is that PDLC-based smart window films can be retrofit onto any window. Applying smart window film to a window is no more complicated than the application of any other window film with the exception of the wiring.
Three companies that sell smart window films that can be installed by a homeowner are:
While it is true that the window film itself is reasonably easy to install, retrofitting wiring, through a wall, to a window location can be challenging. iGlass Technology has a network of installers for their window films for those that don’t want to install the product themselves. Similarly, Smart Tint will sell their window film to homeowners for DIY installation, but recommends installation by professionals, and works with a network of third party installers to assist homeowners.
There are different versions of smart window film that vary by the voltage needed to control them. Window films are available that operate on standard 120 VAC house current. These can be integrated into a smart home by simply wiring them through a smart home dimmer. The window film can then be controlled through, for example, Alexa voice commands.
The above suppliers also can provide power supplies for their low voltage films that can be integrated with a smart home processor/hub. Smart Tint, for example, offers an RS-485 controlled power supply for their low voltage window film. This power supply can be directly controlled from a Crestron automation processor.
Buyers need to remember that these window films only become transparent when voltage is being applied to them. To keep a window transparent requires ~3 watts per square meter of film per hour. So, for every two square meters of film, it is the equivalent of powering a 450 lumen (40 Watt incandescent brightness) LED bulb.
Window films aren’t going to fit the aesthetics of every home. If a house’s décor is based on “minimalism,” they would fit right in. However, smart window film can also be integrated with other window coverings to fit into almost any décor. For example, in a Victorian home, curtain panels can be used to frame a window and smart window film used to provide privacy. In addition, smart window films absorb up to 98 percent of UV rays so they can protect curtain panels, and other furnishings, from fading due to exposure to sunlight.
It should also be noted that smart window films can even be more useful in a commercial setting. Glass-walled conference rooms are very common in today’s offices. But, the glass walls can make occupants feel like they are in a fish bowl. Smart window films are an easy way of providing privacy when a conference room is in use. It is also very common for executive offices to have either a glass door or a door with a window in it. Smart window films are an easy way of providing privacy for an important meeting.
Windows are an important part of any home. There are now high-tech options for the glass to make them more energy efficient, require less maintenance, and integrate them with a smart home system. Smart window films are affordable for consumers and offer a business opportunity for smart home integrators to provide their customers with a unique option for light/privacy control in their homes.