Retractable Awnings Block the Sun

QUESTION: The sun shines in our sliding patio glass door and in the bedroom windows and really bakes us. Are there any special new types of awnings to use and what size should they be?

ANSWER: Awnings are very effective for blocking the sun’s heat from coming in through your windows and doors. Not only will your air-conditioning costs be lower, but your carpeting, drapes and furniture will fade less.

There are some new special retractable awnings that are ideal for patio doors. In addition to shading your sliding glass door, these awnings provide a cover for your patio.

They are available in widths up to 40 feet and project out from your house up to 12 feet. The tough acrylic fabric cover is supported by strong metal arms that are attached to the house.

When you crank the retractable awning open, an elbow joint in each arm straightens extending the awning out over your patio. It is totally supported from the house wall with no supports at the end. When you retract the awning, the fabric cover rolls up on a spring-loaded roller and the support arms are hidden flush against the wall.

For easier operation, you can get an electric motor and controls. You can also get special sun and wind sensor controls to automatically open or retract the awning depending on the weather conditions.

You can use either fixed aluminum or fabric awnings for your bedroom windows. These are fairly easy to remove in the winter if you want to get the maximum amount of sun for passive solar heating.

The proper size of an awning is dependent upon your area’s latitude and the height of the window. Also, the higher the awning is mounted above your window, the bigger the awning must be to give complete shading. The farther north you live, the lower the sun is in the sky, so the awning must project out farther.

You can determine the correct awning size by simply holding a long stick out from the top of your window where the awning will be attached. Angle it at the angle of the awning. Attach clothespins at several positions. By watching where the clothespin shadows fall on your window, you can determine the required size of the awning.

There also are F-factor charts that you can use to determine the proper awning size. They show two numbers for each area’s latitude--one factor is for the proper size on Aug. 21 and one factor for June 21.

You can write to me at the address below for Utility Bills Update No. 221 showing manufacturers, addresses and telephone numbers of retractable and fixed awnings, product specifications and an F-factor chart to determine the proper awning size. Please include $1 and a self-addressed stamped business-size envelope.