Because improperly insulated windows are the cause of much heat loss during the heating season, and for a large amount of energy wasted in summer when the sun's heat is absorbed through the glass while air conditioners are running, a great deal of attention has been paid in recent years to various ways of improving the insulating properties of the average window.

A product recently introduced to accomplish this is an insulating window shade called Window Quilt. According to the manufacturer, Appropriate Technology Corp., P.O. Box 975, Brattleboro, Vt. 05301, these shades will reduce heat loss through a window as much as 40 percent to 50 percent in the winter. In the summer they will cut down the amount of heat absorbed from the sun as much as 60 percent to 70 percent, and they will help keep cool, inside air from escaping to the outside when air conditioners are running.

Prices vary according to the size of the window. For a standard window about 30 inches by 48 inches, one of these insulated shades, with all hardware, will cost about $60. (In rooms that are heated in the winter and air conditioned in the summer, the shades would save enough on utility bills to pay for them in two to five years.)

Window Quilts run on plastic tracks secured to the sides of the window frame with a self-adhesive backing to prevent air from escaping around the edges, or at the top and bottom. The shades are made of a quilted, five-layer "sandwich" of polyester batting with a polyester fabric facing on each side and an aluminized, plastic-foil vapor barrier on the inside. They come in four colors -- white, bone white, camel and navy -- and are custom-made to fit any size window. Either you or the dealer can install them. Battery-Powered Sump Pumps

Many homes depend on sump pumps to keep their basements dry and prevent flooding during wet weather. These pumps sit in a sump, or lined hole, in the basement floor and automatically kick on to pump out water when a sensing device measures a water depth that exceeds the preset minimum. Since these pumps and the automatic switches that activate them depend on household electric power, they often cannot do their job just when they are needed most -- when a storm that can flood the basement also causes a power failure. To eliminate this problem, at least two companies now market battery-operated backup pumps that will take over in the event of a power failure.

ESP Industries, 716 Kensington, Arlington Heights, Ill. 60004, makes two models: a small, submersible Model S-333 that fits into a typical sump next to the regular pump (see accompanying illustration), and a large, upright model that stands on its own brass column. Those are priced at $260 and $360, respectively. Simer Pump Co., 5960 Main St., Minneapolis, Minn. 55432, makes one model, the Ace in the Hole, a self-contained unit that sits next to the sump hole and kicks on whenever water overflows onto the floor, it costs $269.95.

Each of these pumps has a 12-volt motor powered by a heavy-duty storage battery (not included) that is kept constantly charged by the house current (a charger is part of the package). When the water level rises higher than the height of the main (110-volt) pump, the battery-powered backup pump automatically takes over. It will also take over when the main pump breaks down or fails to start, or when the flood is too much for one pump to handle. Pivoting Work Lamp

Combining the usefullness of a grounded, three-prong extension cord with the versatility of a drop light or trouble light that has a powerful magnet in its base so it will stick to the side of metal appliances, pipes, cabinets and car bodies, the Pivotlite also has a ball-joint swivel at the base of the socket that permits rotating the bulb cage and reflector 360 degrees and-or tilting it 170 degrees in any direction. This makes it much easier to use the light in awkward places where you want to tilt or turn so the light won't shine into your eyes (a common problem with most drop lights).

Made by Plymouth Products Inc., 464 Merrick Rd., Oceanside, N.Y. 11572, it comes with a 25-foot cord and costs $29.95. The handle and light cage are made entirely of shock-proof and break-resistant orange plastic. The handle has a built-in light switch and a three-prong receptacle. A chrome-plated, felt-backed, round metal plate available as an accessory ($3) can be screwed down anywhere. The Pivotlite's magnetic base will stick to this firmly, so it can be used as a desk lamp or work light. For Stitchless Sewing

A new clear adhesive that comes in a tube enables anyone to mend or seam most washable fabrics without using needle or thread. Equally useful for attaching ribbons or trim, for applying fabric appliques or even for shortening trousers and skirts and mending torn products or hems, Unique Stitch comes in a half-ounce tube and costs about $2. It is made by Advance Color Corp., P.O. Box 54870, Los Angeles, Calif. 90054, and is sold in hardware and houseware stores, as well as in many department stores and fabric outlets. It should not be used on wools or silks that must be dry-cleaned, or on polyester velours, velvets or fake furs. Chainsaw Sharpener

Built around a compact, high-speed motor that develops 25,000 rpm, the Model 1246 Chainsaw is a chainsaw-sharpening kit that will work with just about any model home saw. Made by the Dremel Division of Emerson Electric Co., 49154 21st St., Racine, Wisc. 53406, the kit includes three aluminum-oxide grinding wheels (5/32 inch, 3/16 inch, 7/32 inch), two spacers and a gauge that makes it easy to set the right sharpening angle for each type of chain blade. The easy-to-use unit costs $39.95, weighs 15 ounces and is a little over 7 inches long. It plugs into any standard household receptacle. a Attic Exhaust Fan

Large attic exhaust fans with the capacity to cool an entire house have been around for some time now, but those large enough to do a proper job have been difficult to install -- especially for the do-it-yourselfer.

The Nutone Division of Scovill Industries, Madison and Red Bank Roads, Cincinnati, Ohio 45227, has introduced a more compact model that is much easier to install. It is small enough to fit between ceiling joists that are 24 inches apart, center to center, and is designed to be easily installed by one man working alone after a suitable size opening has been cut in the ceiling of the top floor (the attic floor).

Called the WHV-20, it is a 20-inch exhaust fan rated at 3,200 cubic feet per minute. It is adequate for most smaller houses and ideal for "zone cooling" of parts of a larger house. This fan (about $239) is enclosed in a housing that has four springlike clips to support it while it is being fastened in place. It comes with a set of weather-stripped louvers that fit into the ceiling opening just under the fan and close snugly when the fan is not running.