When the Arab oil-exporting countries turned off the spigot in 1973, ''energy conservation'' became the buzz phrase for the rest of the decade. Everyone wanted to trim energy consumption in the home, the car, aircraft - you name it.
Homeowners began to insulate, caulk around the windows and doors, wrap the hot-water heater and pipes, and turn down the thermostat.
But this is the 1980s and consumer concern over energy availability has flagged. Motorists, for example, are buying big cars again as drivers demand more performance, not necessarily low fuel consumption.
Yet for the individual homeowner, there are even better opportunities today to save money by trimming back on energy use, primarily because energy costs more today than ever before. While the upward spiral of most energy prices has slowed since the 1970s, costs for electricity, natural gas, and fuel oil have not leveled off.
A kilowatt-hour of electricity and a gallon of fuel oil cost a little more today than they did a year ago. And a cubic foot of natural gas generally costs 20 percent more this year than last.
While there isn't much a homeowner can do about the cost of energy, there are a great many things that can be done to reduce the amount of energy used. Many of these energy-saving steps cost little in comfort, convenience, or cash. In fact, low-cost improvements are often the most profitable in terms of the annual payback.
Most householders must set up spending priorities. Thus, the wisest course of action is to invest first in materials, systems, and equipment that will give the greatest rate of return.
In most homes, space heating (and cooling) and water heating demand attention first. Together, these consume up to 85 percent of the annual energy used. Heating and cooling
In the average home, about $7 of each $10 spent for energy goes to heat and cool living spaces.
Some simple changes in the way a household is operated can trim those costs considerably, with little or no investment in material or equipment. Closing off seldom-used rooms, turning down thermostats at night and when the family is away , and keeping furnace filters clean can add to a home's energy efficiency.
Depending on a region's climate, the simple exercise of turning a thermostat down 5 degrees in winter and up 5 degrees in summer (from the normal 72-degree setting) can save $35 to $120 in yearly heating and cooling costs. Merely lowering the thermostat during the nighttime hours in winter can save half as much.
A set-back, clock-type thermostat will perform this function automatically and costs about $100 to install.
Have a qualified maintenance man inspect the heating and cooling equipment once a year. A competent dealer will charge $35 to $50 for this service, but a poorly adjusted furnace can waste that much fuel in one winter month.
Fuel oil and gas furnaces often need replacing after 12 to 15 years' service. This is a big-ticket item and requires an investment of $2,000 or more, typically. But newer furnaces are considerably more energy-efficient than those built 10 or 15 years ago, so the investment can be recovered sooner in fuel saving.
In areas where natural gas is available at lower cost, homeowners heating with fuel oil may want to switch by changing the furnace or boiler burner. This is also a costly strategy - $600 to $800 for the conversion - and is based on the expectation that natural gas will continue to be cheaper than fuel oil. That, of course, may be a faulty assumption.
''Across the nation, natural gas prices are expected to continue increasing at about 15 percent per year,'' according to James Pastoret, heating-fuel specialist at the University of Missouri. ''At this rate, gas prices will double in less than 5 years.''
Still, gas-fueled furnaces today are 80 to 83 percent efficient. By comparison, older furnaces (built before 1974) are only 55 to 60 percent efficient. That is a better performance than most oil burners give, and should let most homeowners scale down the size of a gas furnace.
A wood-burning fireplace is cheery and inviting, but an open-flue fireplace going full blast can actually waste more heat than it produces by drafting already-heated air up the chimney. The most economical way to close off a fireplace not in use is to close the damper - if the unit has a damper - and cut a piece of plywood to fit tightly over the front of the fireplace.
For fireplaces that are in use, efficiency can be improved by installing tempered glass doors on the front. The glass allows heat to radiate into the room, but reduces the draft of furnace-heated air into the fireplace. Tight-fitting doors for a 40- to 44-inch fireplace cost about $150.
Even more efficient, but more costly, are airtight fireplace inserts that, in effect, convert a fireplace into a wood-burning stove. Some of these units have heat ducts and small blowers to get more mileage from wood heat. Whether the cost of the equipment is repaid over a reasonable length of time, however, depends on firewood prices and how much the fireplace insert is used. Insulation
''Insulation of heated spaces still constitutes the best energy investment most homeowners can make,'' asserts John R. Cusick, a housing specialist with the University of Missouri.
''Add insulation first to the attic,'' he says. ''Heat rises and moves from a warm area to a cold area. Installing or adding insulation in attics returns relatively more money in the form of heating fuel saved than insulating walls or floors.''
Loose-fill types of insulation (glass fiber, mineral wool, or cellulose fiber) can be poured over existing insulation in most attics. For homes in the northern half of the lower 48 states, Cusick recommends insulating attics to a minimum R-33. (R-value describes the insulating property of materials and usually is stated as R-value per inch of thickness.) An 11-inch-thick layer of mineral wool provides R-33 insulation, the same as 9 inches of cellulosic fiber.
For the southern half of the country, where added inches of insulation return relatively less in fuel savings, attics should be insulated to only about R-26.
Most lumberyards that cater to do-it-yourselfers have rental machines with which to blow insulation into attics and wall cavities; many provide the machines free to customers who buy a quantity of insulation. Adding 7 inches of cellulose fiber insulation to 1,000 square feet of attic space would cost $265 to $300 in most regions, and that quantity would secure the free use of the machine at many dealerships.
Getting insulation into the space inside finished walls requires more time and trouble than blowing loose-fill material into an attic, but if the walls are not insulated, the repayment in fuel saved makes the effort worthwhile.
The simplest method is to cut small holes at the top of the wall between each pair of studs. After the insulation is blown into the wall cavity, the holes can be covered with a strip of trim molding. Draftproofing
Windows are great for admitting light, providing a view out-of-doors, and collecting solar energy during the day, but they are not good insulators against nighttime heat loss.
Single-pane glass, in fact, allows about 10 times as much heat loss per square foot as a well-insulated wall. Insulating glass - two panes with air space between - loses only half as much, but this is still five times the heat migration through an insulated wall.
Depending on the square footage of windows, storm sashes can save as much as 15 percent on energy bills, provided that drafts around these openings are also sealed. Custom-made storm-screen combination sashes are convenient but cost $35 or more per window to install.
The air space between glass layers is what provides the insulation. To save money, homemade storm windows built from transparent plastic kits do an adequate job at $10 or less per window.
Insulating shades and curtains helps cut heat loss through windows as well. Insulated window-dressings are made in attractive styles from moderately priced materials. This option may be more attractive, however, if the shades or draperies need replacing anyway.
The Illinois Institute of Technology reports that up to 12 percent of heating and cooling costs can be saved with conventional roll-up shades, simply by using windows to ''track the sun'' during the day. Open the shades on east-facing windows in the morning; south-facing windows during midday; and west-facing windows in the afternoon to let in the sun. This is the simplest, cheapest form of solar heating.
During the air-conditioning season, shades would be opened and closed in reverse order, of course.
Storm windows and insulated curtains don't save much heating energy when loose-fitting frames and sashes let the heat out. Test for air tightness by moving a lighted candle around the frames and sashes of closed doors and windows. If the flame flickers, weatherstripping and caulking are needed.
Caulking and weatherstripping are not big projects for homeowners with minimal do-it-yourself skills. Weatherstripping comes in a variety of types, from adhesive-backed rubber foams to metal strips. Many of these can be installed without tools.
Likewise, caulking compounds vary in composition and cost. Oil- or resin-based caulking is low cost, but the least durable when exposed to the weather. Latex, butyl rubber, and polyvinyl types are medium-priced, but they last longer. Most expensive but most durable are the silicone and polysulfide compounds. Some experts say these are the best buy in the long run, because they stay pliable and do not deteriorate in the sunlight. Other places to save
* Lower the heat setting on water-heater controls to 120 degrees. If your heater has a control dial that reads ''high-medium-low,'' set the pointer at the low side of the medium setting. Water at 120 degrees is hot enough for all household uses, even if you have an automatic dishwasher.
* Flush any sediment from the bottom of a water heater every six months by drawing off two or three bucketfuls of water from the heater drain. Sediment and sludge can build up inside the tank to insulate the water from the heating element which will reduce the heater's efficiency.
* Use cold water, rather than hot, to operate a kitchen garbage disposer. This will not only saves energy needed to heat water, but is also easier on the appliance. Grease tends to solidify in cold water so that it can be ground up and washed away.
* Electric clothes dryers can be vented indoors in the winter. Simply remove the exhaust pipe from the outdoor vent connection, cover the end of the pipe with a piece of cheesecloth or old nylon stocking, and direct the stream of warm air into the house.Plug the outdoor vent to keep the cold air out. But with gas dryers, remember that they should always be vented outdoors for safety.
* When shaving, fill the sink with warm water, rather than letting the hot water run. The energy needed to heat the hot water that's let run for two shavings would power an electric shaver for a year.
By looking around the house, most people can find other ways to make their home more energy-efficient without having to spend a lot of money. The reward will be lower utility bills for years to come. Which energy-saving expenses pay best? Cost Annual Rate of Item (Range) return return (%) Shower-head control $3- 7 Up to $50 1,000 Water-heater insulation $15- $25 $8- $10 50 Clock thermostat $75-$110 $50-$100 80 Heat duct insulat. $80-$120 $30- $50 45 Caulk air leaks $80-$150 $50-$100 65 Pilotless igniter (furnace) $100-$130 $40- $60 40 Vent damper (oil furnace) $150-$250 $20- $60 30 Storm windows (custom-made) $300-$600 $80-$120 27 Attic insulation (adding 6 in. loose- fill material) $260-$400 $45- $65 17 Attic insulation (adding 11 in. to uninsulated attic) $550-$700 $180-$250 33 Cost to install many items will depend on the size of the house, number of windows type of heading system and other variable factors. The cost range shown in for moderate-sized single-family dwellings heated with forced-draft furnace. Likewise, the range of expected returns varies with climate, number of household members and other factors.