As a result of the recent post regarding my unhappiness with tinted windows for long distance passages, I received several potential connections from readers to people who might offer some advice. The most helpful of these contacts was Scott Haddock, former president of the National Glazing Council. Scott has been in the window teatment business for over 30 years, and knows what is available as well as what may be coming in the future.
He explained that there are two basic purposes of glare protection, which is at the heart of this subject, and his comments spanned not just marine, but also commercial and residential windows, doors, skylights, ports, etc. Reducing the heat load is the primary purpose of such window treatments, and then letting in light. But reducing infrared heat load is the primary purpose.
He said that, up until very recently, there have been two basic ways to accomplish UV and heat reduction. The first is an absorbent coating, which is tinting, absorbing the light and reducing the heat. But absorbent treatments tend to reradiate heat regardless of the levels of how light or dark the tint, so is not as popular for most applications.
Much more effective is reflective treatment, which simply reflects the light off the surface, with no ability to store or reradiate energy. Big office buildings that stand like giant mirrors employ this form of efficient glare protection.
Newer thin films are coming onto the scene using "metal sputtering" technology, and they have been successfully used in all-glass buildings in what are called "curtain wall systems." The buildings in modern cities, covered in glass, use these non-structural systems to cover the outside of the building, some totally reflective, some with slight shades of color, and all provide great weather protection and add aesthetic appeal. (While not particularly relevant to our boats, it is interesting.)
What is relevant to boats are the even newer technologies, which include smart glass and smart coatings on glass that use very small amounts of electricity to turn windows, portholes, skylights, and doors from opaque to clear in seconds, and are infinitely dimmable. One reader passed along on this British company: www.theelectricglasspeople.co.uk/electric-ice-technology-yacht.
From Scott's suggestions of where to look, I was able to track down smart glass products offered for marine use. When the power is off, randomly-oriented microscopic crystals absorb light and don't let light through, so the glass appears opaque and uniformly cloudy. It is only when electricity is applied that these crystals align with the current and let light pass through the coating, so the glass becomes clear. Check out: www.smartglass.com/products/#Marine. Its website explains many of the features and benefits of this product line in detail, and I found the FAQs in the Marine section particularly helpful. While the system is AC powered, a DC converter can easily be inserted into the system. The power needed to operate this system is about 1.8 milliamps per square foot.
With the above technology, when you leave your boat at anchor or in a marina, all windows and doors are opaque, providing great protection for the interior fabrics and surfaces. When you are under way, the crew can enjoy a bright cheery saloon or dial in a bit of opacity if desired.
Another company offers self-adhesive film products that do pretty much the same thing for use in home and boat (and yes, DIY is possible) : shop.smarttint.com/Grey-Smart-Cling-Self-Adhesive-installed-on-a-boat_b_515.html. They offer films in colors as well.
Perhaps there are other companies that sell similar products, but it seems clear we have options other than darkly tinted saloon windows. So I am hopeful.
Scott told me as this subject continues to evolve, not all of the promising technologies stand the test of time. But he says not to worry, as what drives continued research and development are the highly attractive potential environmental benefits, which are great motivators for technology companies to find more efficient and "greener" solutions that reduce overall energy resources that would otherwise be required for heating and cooling.
Hopefully these new technologies will benefits owners of cruising boats.
Thanks to all who joined this conversation, and we'll see where this goes next...