Heat loss and gain through your windows can be 10 times more than through a wall of the same area, according to the University of Wisconsin Cooperative Extension. Single-pane windows found in older homes lose even more energy than newer, insulated, double-pane windows, but both allow cold air to enter in the winter and heated air to escape -- with an opposite effect in the summer. Preventing the waste of the energy that you use to cool or heat your home requires insulated draperies. Instead of buying off-the-shelf window coverings, you can construct your own to save money.
Choose closely woven cotton fabric, such as muslin. When function is a higher priority than decor, visit fabric stores and look for bolt ends or remnants. Old bedspreads and comforters from garage sales or thrift stores are cheap sources of fabric that you can repurpose for window coverings. Choosing bedspreads that have a knit or polyester lining gives you an extra layer of insulation.
Fabric stores and craft suppliers often sell rolls of batting for quilting projects. This type of batting usually comes in several thicknesses and a variety of widths. Measure your windows before you visit the stores so you will know how much batting you need. Bubble wrap is an alternative to purchased batting if you can collect enough pieces of the same density to fit your curtain or drapes.
Creating energy-efficient window coverings requires that you place a vapor barrier on the side of the curtain or drape that faces a heated room. Your vapor barrier can be a sheet of clear plastic, such as a painter's dropcloth, or a sheet of Mylar. To prevent heat gain during summer, install the vapor barrier on the window side of your drapes. Black plastic and Mylar help reflect sunlight away from your windows.
Sew or glue your fabric, insulation and vapor barrier together for each drape or curtain. When you are ready to install the window coverings, position them so they fit tightly against each window frame. Hook and loop tape and magnetic tape are two of the most common options for sealing the edges of your insulated window coverings. If you are handy with a needle and thread, adding tabs or ties to the sides and bottom of the drapes lets you use simple cup hooks to tighten the drapes and prevent gaps through which heat or cool air can flow. Adding a cornice board to each window also reduces airflow and lost energy through the top of the window.
- University of Maine Cooperative Extension: Bulletin #7214 - Maine Home Energy: Insulated Window Treatments and Coverings
- University of Florida Cooperative Extension: Window Management for Energy Conservation
- University of Wisconsin Cooperative Extension: Energy Conserving Window Treatments - Insulated Shades and Draperies
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