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The University of
Waterloo's Faculty of
Architecture building
(left), built years ago, is
far more energy
efficient than
modern high-rise
condos in
the GTA.
“Windows are expensive (in terms
of energy loss),” he said. The cheap-
est solution is to reduce the area ded-
icated to them. If the window area is
reduced to 31 per cent (with an R2
value) you would have an overall R rat-
ing of 5.3. If you do the same with
energy efficient R4 windows, you
could reach R8.9 overall.”
“You make trade offs in design,”
he said.
“You make intelligent
choices about how you spend your
money.” There are other issues, he said,
with curtain window walls. As much
as they leak heat in the winter, they
absorb heat from the sun in the sum-
mer, creating truly heavy air condition-
ing loads.
He said buildings built by investor-
owners, rather than for quick resale to
condo purchasers, are being built to
a higher standard.
There are solutions, he said, in-
cluding solar control glass, thermo/
electronic systems that control the
light intensity, and interior and exter-
nal shade and blind systems.
“Curtain walls have very poor ther-
mal comfort performance,” Straube
said. “Specifying better products and
reducing (window) area reduces
costs and significantly improves per-
formance.” “Higher industry performance
should and will be demanded for our
buildings,” he said. “Windows are
the last big hole we have to fix.”
The Canadian Design and Construction Report — Summer 2014 – 13