As windows get more energy efficient,
window selection gets more complex.
Gone are the days when R-value and
air leakage were the only important
window specifications. Open almost
any building magazine, and you will
probably see ads promoting the reduction
of fabric fading with Heat Mirror
windows, the increased solar heating of
LOF Energy Advantage glass, and
reduced condensation with Hurd Insol-
8 windows. These are a few examples of
the latest performance features that
window manufacturers are promoting.
More are sure to follow.
The following suggestions should
help a builder or designer intelligently
navigate this technological maze.
R-value — A Moving Target
When low-e windows were first
introduced ten years ago, they carried a
hefty cost premium over conventional