Small fix-up tasks can slash those big-ticket heating and energy costs

If you plan to tighten up your house for next winter, get your priorities in order. In other words, don't spend a lot of money on energy-saving projects that may net you relatively small savings, while passing up the big energy-saving possibilities that could cost you very little.

It's like rushing into the showroom and buying a $10,000 car that gets 15 miles to a gallon of gas when what you really need is a $6,000 car that gets 30 mpg, warns John M. Marshall, president of Alumabilt Inc. and a leading Boston-area home-improvement contractor.

"Look before you leap," urges Mr. Marshall.

Look around the house to see where the energy-weak spots are, get in touch with component manufacturers, banks, and the Department of Energy for literature that explains what "R" and "U" values are all about as well as other facts on how to save energy, and then go ahead a step at a time with those projects that save the most energy per dollar invested.

Caulking and weatherstripping all the windows and outside doors is the least-costly way of cutting heating costs. Small leaks around windows and doors , for example, can let in a surprising volume of cold air which has to be heated at today's high and rising cost of oil and natural gas.

Look for cracks at window and door frames, at siding corner joints, and along the tip of the foundation where the masonry meets the wood.

Poorly fitting single-glazed windows are a huge energy waster. Caulking and weatherstripping can help out immensely. Obviously, double- or triple-glazed thermal-break windows are much better than single-pane windows, but they cost more money. If your house has old windows that are in satisfactory shape, adding storm windows will make a big difference.

While it may not be aesthetic, installing sheets of clear polyethylene over the windows is a bargain for the energy-conscious homeowner. However, you may not like the appearance.

Every time you open the door to your house, it costs you at least a nickel in wasted energy, says Mr. Marshall. Use a sliding-glass door as little as possible. Insulated shades inside the house, both on the windows and sliding-glass doors, will save energy but the cost could run up to $40 a window unless you make them yourself. Many state university extension services have detailed plans and specifications for energy-conserving drapes. Take advantage of them.

Is your present heating system in good shape and working at peak efficiency? Have it checked out in the summer.

You can insulate all heating pipes and ducts, especially if they go through an unheated garage, a cool basement, or cold attic.

Don't forget that it takes a lot of energy to heat the water in the house. You can wrap the water heater in an energy-saving blanket and also reduce the thermostat setting for the water.

How about installing a wood-and/or coal-burning stove? Of course, they have to meet the requirements of the law, both in manufacture as well as installation.

If you have a fireplace, there are some fire grates which are more energy-saving than others. Be sure to close the fireplace damper as soon as the fire is out.

Don't forget that warm air rises. Thus, a major source of heat loss in your home is right through the roof. If you can get up into the attic or crawl space , you can add loose or batt-type insulation to the floor at very little cost. If your house is built on a slab or over a crawl space, the floors should be insulated as well.

Insulating the sides walls of an already-standing house can run into significant money, however. No matter, it may be the thing to do in your house. Check out the cost.

Ask your local utility company about an energy audit. Federal law requires utilities to provide the audit at low cost or there are energy-audit firms which will do the job at little cost as well. The purpose is to pinpoint the spots where your house is losing too much heat to the outside air.

It should make a lot of sense to your pocketbook. Indeed, a well-insulated house is a sure hedge against rising energy costs.

Numerous instructions and advice on insulation your home are available these days. Two useful booklets are "How to Save Money by Insulating Your Home" and "Save on Home Heating and Coolings Costs: Insulate Your Attic Now." Each booklet is available for 40 cents and a stamped, self-addressed envelope from the Mineral Insulation Manufacturers Association, Dept. SR., 382 Springfield Avenue, Summit, NJ 07901.

You can also write to the Consumer Information Center, Pueblo, CO 81009, and ask for a free copy of the Consumer Information Catalog. In it you'll find many booklets and pamphlets which are available at little or no cost to the public.

Besides that, many companies offer free energy-saving l iterature for the asking.