Standard curtains or drapes can reduce heat loss from a particular room by about 10 percent, depending on the material and how the coverings are installed. Heat is lost through most window treatments through the gaps between the covering and your window. The air that loses heat falls below the bottom and out the sides of the curtains, drawing more hot air in at the gaps above. It is possible to convert your existing drapes to energy-saving window coverings that reduce heat loss by up to 25 percent by stopping the airflow along the top, bottom and sides of the coverings. Enclose the curtain rods at the top to stop hot air from being drawn in. Use drapes or curtains that go all the way to the floor and fit curtains so that they’re tight to the window on all sides using a fabric fastener or magnetic tape to secure them to the wall or window frame. Also use a closed-weave fabric that better restricts airflow. A double layer of drapes adds more air spaces, which reduces convection.
Heat loss can be reduced by up to 28 percent using roller shades. These are often more efficient at preventing heat loss than curtains because they are installed very close to the glass, preventing movement of air. If the edges of the blinds are secured to the window, you can further reduce heat loss by up to 45 percent. Opt for those that have both a light side and a dark side so that you can reverse them with each season. In cold weather, the light side should face inward, to push heat away from the window and back into your home, while the darker side would convert light from the outside into heat.
Plastic insulating kits can reduce heat loss from your windows by up to 50 percent. These kits come in rolls or sheets and typically cover between five and 10 standard windows. Kits are also available for large windows and patio doors. Typically, these are sealed by using a hair dryer to seal the adhesive strips along the sides of the plastic. The heat from the hair dryer shrinks the plastic to form a tight barrier between the window and the plastic. When the cool weather is over, the plastic is removed.
Storm windows are an extra pane of glass that can be permanently attached to your window or put on each winter and removed in the summer. They’re secured on the outside or the inside of the window frame and are ideal for older homes with windows that haven’t been replaced by newer, energy-efficient windows. Storm windows can reduce heat loss by 50 percent and are made of wood or aluminum frames.
Although unattractive, rigid insulating foam panels secured over your window can reduce heat loss up to 85 percent. The foam should be cut to about 1/8 inch longer and wider than your window opening and pressed into the window. These are more ideal for basement windows that aren’t used frequently because they allow no natural light into your home.