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.