ENERGY STAR® & NFRC...TRUST THE EXPERTS
ENERGY STAR was created by the United States Department
of Energy to establish a program for evaluating
the thermal performance of windows and their suitability
for different geographic regions of the country.
Windows must be tested to the National Fenestration
Rating Council (NFRC) standards. Windows must be
certified by an independent third party as meeting
the NFRC test standards and unbiased criteria set
by ENERGY STAR.
All Signature windows with low E glass meet and surpass
these criteria and are ENERGY STAR qualified in all
50 states.
1. U FACTOR: THERMAL INSULATION
The U Factor indicates how easily heat will flow
through the window, whereas R Factor indicates
the opposite: how well the window will resist
heat flow. The lower the U Factor, the better
a window insulates.
2. SOLAR HEAT GAIN COEFFICIENT
Solar Heat Gain Coefficient (SHGC) is the amount
of solar radiation admitted through a window.
The lower a window's SHGC, the less solar heat
is transmitted into the house and the easier
it is to keep your house cool in the summer.
On the other hand, in northern climates a higher
SHGC can provide beneficial passive solar heating
in the winter. Signature offers a variety of high
performance glass coating packages with varying
SHGC ratings to suit your needs, based on your
climate.
3. VISIBLE TRANSMITTANCE
Signature's spectrally selective glass coating packages
have been designed to enhance a window's thermal
performance by blocking ultraviolet and infrared
light, and in turn, block some visible light
as well. Clear glass itself blocks about 20%
of visible light.
4. AIR INFILTRATION
The amount of air that can pass through the seals
of a window's operating sashes, measured by a
fraction of cubic feet per minute per square
foot of window at 25 mph winds.
