Independent tests have consistently shown that heated windows do not lose more heat or power to the outside as outside temperatures become colder. That is, heated windows do not lose their efficiency as the weather becomes colder due to the insulating effect of the heated glass, the relative heated glass temperature and the lower room air temperature, the low-e glass coatings used, the air gap between the glass panes and other factors.
In 2007 and 2008, Kansas State University (KSU) tested the Power*e Glass using their climate chambers and computer simulations and found comparable results.
2007 Tests
Among their findings KSU concluded that Power*e Glass windows:
• Substantially reduce the need for other heating systems
• Produce more consistent and comfortable room conditions than natural gas forced air heating
• Direct 85% of their power to heat the interior - regardless of outside temperatures
• Stop virtually all building heat loss through the heated glass
• Create heated zones that complement other heating systems by reducing a building's heat load.
2008 Study
Using the 2007 information and other data, KSU's 2008 study used an ABOVE computer simulation of a multistory Chicago office building to compare a natural gas heating system and a Power*e Glass system.
KSU's 2008 study calculated the thermal comfort profile, energy consumption and temperature distribution of the occupied office space and found that:
• A Power*e Glass heating system maintains comfortable and consistent temperatures
• The Power*e Glass system (above) used only 1.4 kWh to heat the space comfortably
• The natural gas system (below) required 2.4 kWh to heat the space and made much of the area uncomfortable (red)
• Natural gas heat systems are not able to match the consistent comfort of Power*e Glass windows.
The ABOVE program is the most advanced building simulation system available based upon significant ASHRAE research and performs fundamental energy calculations for radiative, conductive and convective heat transfers.
Additional Benefits
Additionally, studies have found that upgrading to 90% or 95% efficient furnaces is not cost effective in many climates and that it may be more cost effective to upgrade to 80% efficient furnaces. In reaching this conclusion, consideration was given to average efficiencies of installed systems, duct losses, infiltration losses, new furnace standards and the impact of costs on upgrading systems to more efficient furnaces. (Electricity and Natural Gas Efficiency Improvements for Residential Gas Furnaces in the U.S, Lawrence Berkeley National Laboratory, Berkeley, California; http://ees.ead.lbl.gov/bibliography/electricity_and_natural_g
Power*e™ is a registered trademark of Radiant Glass Industries, LLC.