How to Save Energy from Windows

Windows

Windows can be one of your home's most attractive features. Windows
provide views, day lighting, ventilation, and solar heating in the
winter.

Unfortunately, they can also account for 10% to 25% of your heating
bill. During the summer, sunny windows make your air conditioner work
two to three times harder. If you live in the Sun Belt, look into new
solar control spectrally selective windows, which can cut the cooling
load by more than half.

If your home has single-pane windows, as almost half of U.S. homes do,
consider replacing them. New double pane windows with high-performance
glass (e.g., low-e or spectrally selective) are available on the
market. In colder climates, select windows that are gas filled with
low emissivity (low-e) coatings on the glass to reduce heat loss. In
warmer climates, select windows with spectrally selective coatings to
reduce heat gain. If you are building a new home, you can offset some
of the cost of installing more efficient windows because doing so
allows you to buy smaller, less expensive heating and cooling equipment.

If you decide not to replace your windows, the simpler, less costly
measures listed below can improve their performance.

Cold-Climate Window Tips

• You can use a heavy-duty, clear plastic sheet on a frame or tape
clear plastic film to the inside of your window frames during the cold
winter months. Remember, the plastic must be sealed tightly to the
frame to help reduce infiltration.

• Install tight-fitting, insulating window shades on windows that
feel drafty after weatherizing.

• Close your curtains and shades at night; open them during the day.

• Keep windows on the south side of your house clean to let in the
winter sun.

• Install exterior or interior storm windows; storm windows can
reduce heat loss through the windows by 25% to 50%. Storm windows
should have weather-stripping at all moveable joints; be made of
strong, durable materials; and have interlocking or overlapping
joints. Low-e storm windows save even more energy.

• Repair and weatherize your current storm windows, if necessary.

Warm-Climate Window Tips

• Install white window shades, drapes, or blinds to reflect heat away
from the house.
• Close curtains on south- and west facing windows during the day.

• Install awnings on south- and west facing windows.

• Apply sun-control or other reflective films on south-facing windows
to
reduce solar gain.

Long-Term Savings Tip

• Installing new, high-performance windows will improve your home's
energy performance. While it may take many years for new windows to
pay off in energy savings, the benefits of added comfort and improved
aesthetics and functionality may make the investment worth it to you.
Today, many new window technologies are available that are worth
considering. Glazing materials (the glass part of the window) now come
with a variety of selective coatings and other features; frames are
available in aluminum, wood, vinyl, fiber glass, or combinations of
these materials. Each type of glazing material and frame has
advantages and disadvantages.