Shading devices: dealing with skylight on you terms.

Both exterior and interior shades control heat gain. Exterior shades are generally more effective than interior shades because they block sunlight before it enters windows. When deciding which devices to use and where to use

them, consider whether you are willing to open and close them daily or just put them up for the hottest season. You also want to know how they will affect ventilation. Exterior <shading devices include awnings, lovers, shutters, rolling shutters and shades, and solar screens. Awnings are very effective because the block direct sunlight. They are usually made of fabric or metal and are attached above the window and extend down and out.

A properly installed awning can reduce heat gain up to 65% on southern windows and 77% on eastern windows. A light-colored awning does double duty by also reflecting sunlight. Maintaining a gap between the top of the awning and the side of the house helps vent accumulated heat from under a solid- surface awning. If you live in a climate with cold winters, you will want to remove awnings for winter storage, or by retractable ones, to take advantage of winter heat gain.

Roughly 40% of the unwanted heat that builds up in your home comes in through windows. The amount of drop (how far down the awing comes) depends on which side of your house the window is on. An east or west window needs a drop of 65% to 75% of the window height. A south-facing window only needs a drop of 45% to 60% for the same amount of shade. A pleasing angle to the eye for mounting and awning is 45 degrees. Make sure the awning does not project into the path of foot traffic unless it is at least 6 feet 8 inches (2 meters) from the ground. One disadvantage of awnings is that they can block views, particularly on the east and west sides. However, slatted awnings do allow limited viewing through the top parts of windows.

Louvers are attractive because their adjustable slats control the level of sunlight slats control the level of sunlight entering your home and, depending on the design, can be adjusted from inside or outside your house. The slats can be vertical or horizontal. Louvers remain fixed and are attached to the exteriors of window frames.

Shutters are movable wooden or metal covering that, when closed, keep sunlight out. Shutters are either solid or slatted with fixed or adjustable slats. Besides reducing heat gain, they can provide privacy and security. Some shutters help insulate windows when it is cold outside. Rolling shutters have a series of horizontal slats that run down along a track. Rolling shades use a fabric. these are the most expensive shading options, but the work well and can provide security. Many exterior rolling shutters or shades can be conveniently controlled from the inside. One disadvantage is that when fully extended, the block all light.

Solar screens resemble standard window screens except they keep direct sunlight from entering the window, cut glare, and block light without blocking the view or elimination air flow. They also provide privacy by restricting the view of the interior from outside your house. Solar screens come in a variety of colors and screening materials to compliment any home. While do-it-yourself kits are available, these screens will not last as long as professionally built screens.

Although interior shading is not as effective as exterior shading, it is worthwhile if none of the previously mentioned techniques are possible. There are several ways to block the sun's heat from inside your house.

Draperies and curtains made of tightly woven, light-colored, opaque fabrics reflect more of the sun's rays than they let through. The tighter the curtain is against the wall around the window, the better it will prevent heat gain. Two layers of draperies improve the effectiveness of the draperies' insulation when it is either hot or cold outside. Venetian blinds, although not as effective as draperies, can be adjusted to let in some light and air while reflecting the sun's heat. Some newer blinds are coated with reflective finishes. To be effective, the reflective surfaces must face the outdoors. Some interior cellular (honeycombed) shades also come with reflective mylar coatings. But they block natural light and restrict air flow. Opaque roller shades are effective when fully drawn but also block light and restrict air flow. Ventilated attics are about 30 degrees F (18 degrees C) cooler than unventilated attics.