We are all aware of window upgrade needs for our homes. We know the benefits
associated with adding insulative qualities to our windows. Not until recent
times has there been an architecturally acceptable, cost-effective option for
commercial buildings to increase comfort, dramatically reduce noise infiltration,
and pay for these improvements with energy savings.
Typically, buildings have focused on saving energy with automation systems and more efficient chillers and boilers, but have not, until recently, looked at the basics of insulating the windows or curtainwall. Window replacement has been considered and used as a last resort by many properties. However, window replacement is a very costly and disruptive solution, generally only used when windows have deteriorated beyond acceptable limits. The better paybacks for window replacement typically run around 20 years, putting them far beyond consideration as an energy conservation measure.
There are several alternatives to window replacement that have proven beneficial and should be a viable consideration for buildings of any age. The most common, basic, and inexpensive is the plastic that shrinks to the window frame. Thousands of these kits have solved problems in Class C and D buildings for years.
A more permanent, more attractive solution is interior insulating windows, also called retrofit "inside storm windows." There are various interior products that are all about the same price and perform quite well. Some are glass products, and some are acrylic. The frames vary from aluminum to vinyl to wood. The aluminum and wood frames are available in a variety of colors. The vinyl frames have been somewhat limited in color selection; however, the overall insulative performance of vinyl and wood are superior to aluminum.
The attachment design is a major consideration. There are some very creative products with well-detailed attachments having minimal profiles. These interior windows blend beautifully with the prime windows, making the retrofit window "transparent." A well-designed interior insulating window is normally acceptable to all Historic Preservation organizations. Fixed and operable models are available. Interior insulating windows can be an attractive upgrade to the interior aesthetic of a building.
The applications are expanding for the retrofit window industry. One of the better products offers a between-the-glass blind option that can be operated manually with a twist knob, remotely, or automatically with a solar sensor. Between-the-glass blinds are terrific at reducing solar heat gain.
The installation process is also a consideration. There is a range of difficulty. Installation can be a very clean and quick procedure. There should be little, if any, downtime for the building.
Working with a company that has a good track record and experience with installation of the product is very important. Like most products, windows are only as good as the people working with you on the project. At least one distributor offers a free energy evaluation that not only gives the cost of the product, but also details the projected energy savings.
Stephen P. Duerkop, CPM, is president of Maine Glass Corp. (www.maineglass.com), Park Ridge, IL (888-825-6975). His past experience includes senior management at JMB Realty Corp., with responsibility for properties of all types throughout the U.S. mainland.