is insulated glass?
Actually, insulated glass is a misnomer, but
it is often used to describe energy-efficient windows. What
the term means is that there are two or more panes of glass
separated by insulation at the edges and air or gas in the
center. The result is greater thermal efficiency.
is air infiltration?
Air infiltration is the amount of air leaking into a building
through any kind of opening. The amount of cold or hot,
humid air entering the house determines how hard the heating
or cooling system has to work, and windows and doors are
a prime source of air infiltration. Look for a low rate
of air infiltration when you choose your windows and doors.
is a gas-filled window?
Modern window technology seals an inert gas (usually argon)
between the panes of glass. The gas is a far better insulator
than plain air, so it further increases the windows
What is Low-E glass?
Low-E stands for low emittance. Simply put, the glass is
coated with a virtually clear material that acts to cut
the transmission of ultraviolet rays from the outside to
inside. Low-E glass improves the thermal efficiency of the
window, cuts glare and prevents damage that ultra-violet
rays can cause to interior furnishings. If you are in a
climate that has long, hot summers, Low-E windows can make
a Big difference in your air-conditioning bill, too.
is the difference between R-value and U-value?
Essentially R-value and U-value are two sides of the same
coin. The term R-value usually refers to such things as
wall and ceiling insulation value, but it does not translate
well to windows. So the window industry uses U-values to
measure the rate of non-solar heat loss or gain instead.
A low U-value indicates that the window does a good job
of keeping out the heat and cold.
is solar heat gain coefficient (SHGC)?
A. The SHGC indicates how much solar radiation enters a
building through a window and is expressed as a number between
0 an 1. The lower the SHGC, the less solar heat it transmits.
SHGC can refer to the entire window, or to only the glass