Last winter, Walter Glowacki's home in Silver Spring ran out of heating oil. By the time he got his 275-gallon tank refilled, the temperature in his house had dropped to 50 degrees.

This year Glowacki decided to buy an insurance policy - a brand new, 2,000-gallon tank that can hold enough oil to get him through at least this winter, and possibly the next.

"I just don't like the idea in the middle of the winter of wondering if they'll come and give you the oil," he explained.

Like many Americans who have agonized in the lives of the Gas Crunch of '79, Glowacki is bracing for the nation's next energy trauma - the heating oil shortage of 1980. $ tIn their grimmest analysis, energy experts paint a picture of school closings, curtailed business hours, and families huddled together in frigid homes waiting for deliveries of heating oil priced at well over $1 a gallon.

Their brightest scenarios are not exactly comforting: tight supplies, spot shortages and sharply rising prices that could boost the heating bills of the average Washington area family by $500 a year.

"The gasoline shortage was an inconvenience for all of us," said Chuck Clinton, the District of Columbia's energy director. "But shortages of heating oil may be a matter of life and death."

The signs at this point are worrisome.

First, supplies of heating oil are so low here - distribution from major oil companies has been cut as much as 65 percent - that local dealers are limiting new customers and falling far behind in their traditional summer fill-up of storage tanks.

Stocks of independent wholesale terminals - which store fuel for many local dealers - are 20 percent lower this year than last, and terminal operators have lined up contracts for only two-thirds of the oil they had procured at the same time last year.

Then, there is price. The homeowner in this area who paid an average of 42 cents for a gallon of heating oil last February spends 77 cents today, and some local dealers expect the price to rise to 90 cents or a dollar by Christmas.

Apartment and office owners here calculate that heating with oil this winter will cost them an extra $250 a unit. This financial burden, they say, will be recovered by rent surcharges of more than $20 each month for their tenants.

For homeowners unable to pass along the added fuel costs, the hardship will be severe. A federal energy official testified recently that rising prices will "put necessary supplies of heating oil beyond the reach of some lower and middle income families."

Oil company officials insist the current shortage is temporary. Once their refineries get extra crude oil promised by Saudi Arabia and begin shifting production from gasoline to heating oil, they say, America will have enough fuel to stay warm this winter.

But even if refineries are able to meet demand this winter, oil executives concede, the consumer costs will be high, not only in the soaring, unregulated price, but in the reduced production of gasoline - which is made from the same raw material, crude oil.

Gearing up refineries for the cold season means sacrificing millions of gallons of gasoline. The tradeoff of heating oil for gasoline raises the specter of more gasoline lines this winter.

"We'll have enough heating oil, come hell or high water," predicted Ed Murphy, director of statistics for the American Petroleum Institute. "The question is how much is it going to cost and how much crude is going to be left for gasoline."

Even the rosiest predictions fail to reassure many of the 150,000 home heating oil users in the Washington area - one of every three homes here is heated by oil - who began preparing for the long cold winter months before the first frost.

Scores of them have followed Walter Glowacki's example, plunking down as much as $1,300 for behemoth backyard tanks they hope will serve as a hedge against escalating heating oil prices and scarce supplies during the winter months.

Thousands more are simply giving up on oil, and turning to cheaper, more plentiful natural gas. Eighty apartment buildings and 100 homes have converted to gas heat in recent weeks, and thousands of requests are pending, said Washington Gas and Light Co.

Other homeowners have invested in new furnaces that alternate use of oil with wood and coal, cleaned their old furnaces for more efficient burning and lowered the temperatures of their water heaters. Persons on fixed incomes are joining budget plans.

In Montgomery County, school officials who have watched fuel costs skyrocket in the past year are studying the possibility - "very remote," they say - of operating the school system on a four-day week as an energy conservation measure.

The growing public fear of a heating oil shortage this winter the precautions and the distressing supply and price outlook today - three months before the start of the heating season - all serve as important benchmarks of the looming crisis.

A far more significant - and startling - measure lies within the ledgers of the major oil companies.

Every year at this time the oil companies begin replenishing their inventories to augment heating oil production during the busy winter months. For the past four years, their storage tanks have contained an average of 240 million barrels by Oct. 1. This year, worried that suppliers were overly concentrating on gasoline production and lagging behind schedule for heating oil buildings, the Department of Energy made a point of asking them to begin working toward that target.

Their progress has been slow thus far too slow, in recent opinion of Deputy Energy Secretary John F. O'Leary. As of July 6, the companies were still 92 million barrels short of the goal and 15 million barrels behind last year's pace.

Since the end of the last heating season, stocks have increased by only 33 million barrels, and most industry officials predict that no more than 230 million barrels will be in storage by Oct. 1 - an amount, they contend, that is still enough for the winter.

Other oil executives and distributors are less optimistic, questioning whether the industry can go over 200 million barrels by Oct. 1 without a strict DOE mandate directing them to step up heating oil production at the expense of gasoline."

Today's stockpiling problems, and the heating oil shortage itself, are rooted in decisions made last year when oil companies allowed their heating fuel inventories to dwindle to very low levels - 115 million barrels - by the end of last March.

The depletion was especially severe in one of the coldest regions of the nation - the Northeast - where 18 major oil companies watched their stocks drain down to half the inventory level of April 1977 and two-thirds the level of April 1978.

Understanding the reason for such drastic inventory drawdowns requires an explanation of refinery production schedules. Refineries normally manufacture gasoline at maximum levels until the fall when they begin shifting production to heating oil.

Last year, however, the industry continued to put out gasoline at peak levels far into the fall and winter to keep with the unusually high gasoline demand. In the process, they sacrificed millions of gallons of heating oil.

When the weather turned cold and demand for heating oil outstripped daily production of the fuel, the oil companies quickly began depleting their stocks to meet heating needs. The especially cold February further diminished the inventories.

Now, while the industry scrambles to refill storage tanks and recover from last year's slow start, the major companies have cut their oil distribution by as much as 65 percent - the first sign of general shortages as the heating season nears.

The pinch is being felt at every level.

Unable to get heating oil from the major oil companies, wholesale terminal operators and local retail dealers are turning increasingly to more expensive independent suppliers and the "spot market" - fuel sold on the open market that is not under contract by one of the major oil companies.

Even those less conventional sources are not always able to meet the growing demand. One day this week, officials of a wholesale terminal in Alexandria - Fannon Petroleum Services - looked everywhere for fuel to put in its nearly empty tanks. It had little luck.

Amato Inc., a heating oil firm in Silver Spring, whose supply has been cut almost in half this summer, would have come to a standstill if not for an emergency grant of 28,000 gallons from Maryland energy officials, said vice president Bob Amato.

"Normally, this time of year, oil dealers are out like busy little bees filling up everybody's tank so they'll be ready for winter," said Jim Windsor, executive vice president of the Oil Heat Association of Greater Washington. "This year, forget it."

The problem of supplying heating oil for residential use is complicated by the competing demand for the precious fuel - known in the industry as Number 2 distillate. It is used as diesel fuel for trucks and barges and power plant fuel for utilities.

"We're scared to death," said Lana Batts, an economist for the American Trucking Association. "When push comes to shove, the home heating oil (customers) are going to get it. There's no politician in the world who's going to have cold homes to keep the freight rolling."

As supply tightens, prices are exploding. Forced to acquire more of their summer stock from independent wholesale suppliers who charge up to 9o cents a gallon, retail dealers are raising their rates higher and higher for residential users.

The outlook is not expected to brighten much once the major oil companies resume providing a steady supply. When the recent crude oil price increases imposed by the Organization of Petroleum Exporting Countries are figures in the wholesale price charged by the major companies is likely to hit at least 70 cents a gallon.

By the time the heating oil flows into the tanks of Washington area homes this winter, the price is expected to reach 85 cents a gallon - more than double last year's rate. Prices could rise even further if shortages occur and dealers turn to the spot market.

For the average home heating customer in this area who uses 1,200 gallons a year, the cost of staying warm could jump an extra $500. Add to that the $360 a year more a two-car family now pays to cover recent increases in the price of gasoline.

For Lucille Spain, 63, a housecleaner from Northwest Washington, the thought of spiraling fuel costs is chilling, even in July. "I'll just have to do without some things just to keep warm," she said. CAPTION: Picture 1, Bill Collins loads fuel oil truck at Stewart Petroleum, Picture 2, winds output hose after servicing D.C. customer, Picture 3, An Exxon holding tank at Newington, Va., tank farm. Emphasis on gasoline led to heating oil shortage. By John McDonnell - The Washington Post