Ballarat & Daylesford Window Coverings
You can choose window treatments or coverings not only for
decoration but also for saving energy. Some carefully selected window
treatments can reduce heat loss in the winter and heat gain in the summer.
Window treatments, however, aren't effective at reducing air leakage or
infiltration.
Window
awnings can reduce solar heat gain in the summer by up to 65% on south-facing windows
and 77% on west-facing windows. You can use an awning to shade one window or
have an awning custom-made to shade the entire side of your house. In the
past, most awnings were made of metal or canvas, which need to be re-covered
every five to seven years. Today, awnings are made from synthetic fabrics such
as acrylic and polyvinyl laminates that are water-repellent and treated to
resist mildew and fading. Whatever the fabric, you should choose one that is
opaque and tightly woven. A light-colored awning will reflect more sunlight. Awnings
require ventilation to keep hot air from becoming trapped around the window.
Grommets (eyelets) or other openings along the tops and sides of an awning can
provide ventilation. The awning may also open to the sides or top to vent hot
air.
You can
roll up adjustable or retractable awnings in the winter to let the sun warm the
house. New hardware, such as lateral arms (pivot arm awnings), makes the rolling up process quite
easy.
Window
blinds—vertical or horizontal slat-type—are more effective at reducing summer
heat gain than winter heat loss. Because
of the numerous openings between the slats, it's difficult to control heat loss
through interior window blinds, but the slats offer flexibility in the summer.
Unlike shades, you can adjust the slats to control light and ventilation. For
example, when completely closed and lowered on a sunny window, highly
reflective blinds can reduce heat gain by around 45%. They can also be adjusted
to block and reflect direct sunlight onto a light-colored ceiling. A
light-colored ceiling will diffuse the light without much heat or glare.
Curtains & DRAPeS
A
curtain or drapery's ability to reduce heat loss and gain depends on several factors,
including fabric type (closed or open weave) and color. With such a wide
variety of draperies available, it's difficult to generalize about their energy
performance. During
summer days, you should close draperies on windows receiving direct sunlight to
prevent heat gain. Studies demonstrate that medium-colored draperies with
white-plastic backings can reduce heat gains by 33%. Draperies also stay cooler
in the summer than some other window treatments because their pleats and folds
lose heat through convection. When
drawn during cold weather, most conventional draperies can reduce heat loss
from a warm room up to 10%. Therefore, in winter, you should close all
draperies at night, as well as draperies that don't receive sunlight during the
day. To reduce
heat exchange or convection, draperies should be hung as close to windows as
possible. Also let them fall onto a windowsill or floor. For maximum
effectiveness, you should install a cornice at the top of a drapery or place
the drapery against the ceiling. Then seal the drapery at both sides and
overlap it in the center. You can use Velcro or magnetic tape to attach drapes
to the wall at the sides and bottom. If you do these things, you may reduce
heat loss up to 25%. wo
draperies hung together will create a tighter air space than just one drapery.
One advantage is that the room-side drapery will maintain around the same
temperature as the interior space, adding to a room's comfort.
High-reflectivity
window films help block summer heat gain. They are best used in climates with
long cooling seasons, because they also block the sun's heat in the winter. The
effectiveness of these reflective films depends on:
-
Size of window glazing area
- Window orientation
- Climate
- Building orientation
- Whether the window has interior insulation.
Silver,
mirror-like films typically are more effective than the colored, more
transparent ones. East- and west-facing windows, because of their greater
potential for heat gain, can benefit more from these films. North-facing
windows won't benefit from them, and south-facing windows may benefit somewhat,
but the benefit could be offset by the reduction of heat from the winter sun.
