Older buildings save energy with window shades!

Posted February 3, 2011, 3:07pm EST

Source: Monster Commerical, January 17, 2011

Straightforward, serious energy conservation.

The North Amercian commercial real estate industry has inherited large stocks of buildings that were designed and built before there was a concern for energy use.  Schools, offices, apartment buildings, hotels and motels were constructed with the belief that energy would always be available and inexpensive.  Fully 49% of the energy used in large buildings each year is devoted to heating and cooling.  This outstrips even the transportation sector in terms of sheer volume.

Lines of heating registers under single pane windows stretch the length of classrooms.  One side of a building constructed in the 50’s or 60’s will be freezing while the other side is baking, requiring heating and cooling plants to operate at odds with one another.  Or worse yet, Victorian era cast iron radiators located under leaky old double hung windows (often historically protected) are warmed by hot water from oil-fired furnaces several floors away.  And no one, especially the Budget Directors, are happy or comfortable.

Most of these buildings have large windows.   Quite often they are expanses of glass stretching from floor to ceiling and wall-to-wall.  Architects at the time knew they would be the source of extremes in temperature and placed the heating and cooling registers right at, and pointed to, the source of the problem – ensuring that all the conditioned air would be forced up against the glass.

For architects in the 1950’s the term “green house gas emissions” would have fostered cartoon images of belching cucumbers – not vapors threatening our climate.  Now we know that the energy choices we make, the fuels we use to condition the buildings we live and work in, have environmental consequences.  We can no longer afford the waste that is inherent with these buildings.

Window manufacturers have spent many years and great sums of money to educate us into believing that new windows would solve these problems.  At first it was aluminum framed storm windows.  Add another piece of glass with no insulation value to the one already there – that has no insulation value.  Then it was double glazed windows.  Go from an R-Value of less than 1 to an R-Value of less than 2.  Wow!

Now even new “high performance” windows average an R-Value of 2.2, the most expensive are rated at about 4.5.  Expensive, disruptive to install and they still don’t solve the problem or approach the ideal wall value of 19.  (And they usually come with an ROI of about 30 to 40 years.)

Many government are no longer including replacement windows in their home weatherization programs as the return on investment is nearly non-existent.  A study was recently completed in the U.K. showing the results of various energy conservation measures employed in different homes near Bristol.  Please note that “high performance windows” rank at the very bottom of the list.

(Information above supplied by Forum for the Future and Arup.)

Now we know we need to do better than that.

The oil crisis of the 1970’s started people thinking about the need for energy conservation.  By the end of that decade a few companies had designed effective window insulation products in an effort to address energy lost through glass.  HeatSaver® Thermal Shades was among them.  In the U.S., President Carter’s tax incentives helped a great deal.  Once those incentives expired so did any serious attention to energy conservation.  We all went back to our profligate ways.

In 1985 HeatSaver installed 160 HeatSaver® Thermal Shades, covering 6,500 sq. ft. of single pane windows, in a private university library outside of Denver, Colorado.  The majority of those shades are still saving energy and in operation today.

Denver project: saved heating air conditioning costs

In order for any window insulation product to be truly effective it must address all four types of energy loss.  Conduction, convection, radiation and infiltration.  If any of these are neglected, performance, and hence return on investment, is compromised.  This means that the product must seal on all sides of the windows, and have both insulation and reflective film layers. 

Given the wide variety of window designs that we have inherited and are thus responsible for, finding a window insulation product that will not compromise quality or performance while addressing all these variables responsibly is not always an easy task.  Until you find the right company.

If properly installed and managed well designed thermal shades should pay for themselves in 6 to 7 years.  Tax programs now available in Canada and the U.S. can bring ROI down to 1 to 3 years.  The savings beyond that go straight to the bottom line, something even Budget Directors can cheer about!

HeatSaver Thermal Shades were designed to be thin, attractive and durable while not compromising the primary goal of stopping energy loss due to the presence of glass.  As all of our shades are custom manufactured in the U.S. for each client, there are very few window designs we cannot address.