Windows
with wood frames have higher R-values, which is the
measure of thermal resistance.
In addition, wood window frames are not affected
by extreme temperature.
Even in cold winters, wood is usually still warm
to the touch and remains at room temperature during in
the hot summers. Another
benefit of wood windows is that they generally don’t
encourage condensation.
There
are some disadvantages with wood frames, however.
Most wood frames are crafted from pine, and do
require a significant amount of maintenance, including
periodic painting, or finishing which will greatly
reduce the swelling, warping, sticking and rotting of
the frames.
If
wood window frames are for you, then you want to choose
window frames made with FSC-certified wood. The Forest
Stewardship Council is an international organization
that works to promote responsible management of the
world’s forests.
Unfortunately, there are a limited number of
window manufacturers who use FSC-certified wood as a
standard frame material.
For energy efficiency, you want to look for
Energy Star and NFRC (National
Fenestration Rating Council)
certification with a U-factor of 0.25 or lower.
The NFRC test windows and doors for heat loss
(U-value), R-value, and solar heat gain.
