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How to Get Your Drapes to Insulate Your Windows: The Importance of a Good Seal

written by: 00orange00•edited by: Donna Cosmato•updated: 2/4/2011

Most drapes don't actually insulate the windows that they are covering. Here is how to turn your drapes into genuine movable window insulation.

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    Drape Insulation: How to Install Drapes so That They Work

    Usually, drapes in people’s homes are not effective at insulating the windows because they are not properly sealed around the edges, or they are not thick enough. However, if you are hoping that you can use your drapes or curtains to insulate your windows, it is very possible. You simply need to make sure your drapes are set up correctly to do the job.

    When you consider how to install drapes, the first thing to remember is that regardless of how thick and impressive a curtain or drape may be, unless you eliminate the convective movement of air over the surface of a window behind it, the majority of the insulating benefit of a curtain or drape is lost. When a curtain is closed, the air trapped behind the curtain and in contact with the glass loses its heat to the cold glass and becomes colder and heavier than the warm air that is still in the room. The object at this point is to keep the air behind the curtain from moving out. Without something preventing it, this cold, heavier air tends to run down into the room.

    This is why it is very important to seal the curtain tightly against the bottom and the sides of the window frame, (or against the floor if you are dealing with full length drapes). If you do not seal these areas tightly, the cold air that is trapped behind the curtain will hurry down and drop below the lighter, warmer room air.

    In effect, this cooler air pools on the floor below (where your feet will feel it). Meanwhile, warmer air above the curtain is drawn in behind the curtain to replace the cooled air that just ran down and out, and so on. So much for being protected from the cold window glass; the cold from the window glass is being brought to you directly on the air currents.

    To prevent this from happening, make sure that the drapes rest firmly upon the floor or the window sill, as the case may be. This can be done by weighing down the bottom of the curtain or drape with a chain or a sand-filled pouch. Alternatively, on a window sill, you might ensure a good bottom seal with the addition of a cord which is run through the hem of the curtain but which allows the curtain to be slid open or closed. This would be similar to the manner in which a curtain might slide along a cord at the top. Matching magnetic strips could be applied to the sill and to the bottom of the curtain or a metal clamp-strip could be fastened to the side of the sill at the bottom of the curtain. If your present drapes or curtains do not reach far enough to make a good seal with the floor or window sill in this manner, you may need to add some length to them.

    Although the top of the drapery or curtain is not as critical, establishing some type of seal is good here too. Valences along the top of curtains can serve to provide a seal of sorts.

    The sides of the curtains or drapes need to make good contact with the window frame or the surrounding walls. They can be fastened with tacks or Velcro strips. At the center, where the two curtains or drapes are drawn together when they are closed, there must be a secure means of fastening these two edges together with no gaps.

    A fastening system could be employed with snaps, zippers, ties or matching magnetic strips. On the other hand, if it is possible, and the curtains are long enough from side to side, they could be supported on parallel rods at the top and drawn right over one another at the center for a couple of feet. This would also serve to seal the middle edge.

    This is how to install drapes so that they seal around the window properly. Using these methods, you will be able to prevent convective heat losses from taking place. This is the first part of correct drape installation for drape insulation purposes. Read on to see how to make your drapes able to reduce conductive and radiant heat losses as well.

Insulating Windows

Windows loose a great deal of a homes heating of cooling input. There are many ways to insulate windows. If you are working on cutting energy costs, or preparing for solar heating or cooling one of these approaches may be useful to you.
  1. Insulating Your Windows
  2. How to Get Your Drapes to Insulate Your Windows: The Importance of a Good Seal
  3. How to Insulate Windows with Curtains or Other Window Treatments