Energy Efficient Window Treatments

Window treatments or coverings are often thought of as decorative.  But some carefully selected window treatments can reduce heat gain in the summer and heat loss in the winter by up to 50 percent.  Here are some things to think about:

Draperies

• Draw them to keep sun out in the summer and warmth in during the winter.
• To increase thermal efficiency, hang them as close to the window as possible.  Also let them fall onto a windowsill or floor and use magnetic tape to attach them to the wall at the sides and bottom.  For maximum effectiveness, install a cornice at the top of the drapery or place the drapery against the ceiling.
• Two draperies hung together and separated by an air space will add even more benefit and increase a room’s comfort – with the room-side drapery maintaining around the same temperature as the interior space.

Blinds

• More effective at reducing summer heat gain than winter heat loss.
• Highly reflective blinds can reduce heat gain by around 45% when completely closed on a sunny window.
• Can also block heat and reflect direct sunlight onto a light-colored ceiling – which will diffuse the light without adding much heat or glare.

Window Shades

• When properly installed, one of the simplest and most effective treatments.
• Mount as close to the glass as possible with the sides of the shade held close to the wall to establish a sealed air space.
• Dual shades offer greater efficiency
  • Highly reflective on one side (white) and heat absorbing (dark) on the other side.
  • Reverse for seasons with the reflective side always facing the warmest side.
  • These shades need to be drawn all day in order to be effective.

Awnings and Overhangs

• For awnings, choose a fabric that is opaque and tightly woven.  Light colors reflect more sunlight.
• Small, horizontal awnings or overhangs will completely shade a south-facing window during the summer, but an east or west-facing window needs coverage that extends down a large percentage of the window.

More Information

Details about various types of awnings, specifications for overhangs and info about shutters, reflective films, insulated panels and mesh window screens can be found at energysavers.gov