The war against energy waste descended on the offices, stores, supermarkets and restaurants of Washington yesterday with no small amount of confusion and decidely mixed results.

Most citizens accepted the new temperature rules with stiff, albeit sweatbeaded, upper lips. But there were plenty for whom a few degrees of air conditioning in the national interest was a sacrifice simply too great to make.

"We'd collapse" at 78 degrees, said Helen Elleni, secretary to the president of Crystal City's Services National Bank, in Arlington where the thermostat remained frozen at 70 degrees.

One teller has asthma, and the computer can't stand the heat anyway, Elleni said. "I think banks should be exempt."

Edgar Diaz, manager of the El Caribe restaurant on Columbia Road, was another of the defiant ones, "When the place gets packed up, people gonna get hot. When people get hot, they gonna go."

He plans to keep the El Caribe thermostat at 70, he said, though even 78 is far cooler than his home country of El Salvador. Diaz, 27, said he never even saw an air conditioner until he was 10.

But there were some who walked that extra mile.

At a bar at 20th and M Streets NW, a topless-bottomless dancer who said her name was Sally Does stepped from the stage with a light mist of sweat shimmering on her body and mourned the mounting heat.

"I do a lot of dancing up there, honey," she said, "and I get hot. . . real hot."

Since the first nonindustrial cooling machine clicked on in a movie house in 1922, America has given much of the rest of the world air conditioner envy.

But yesterday's new rules threw people into varying states of confusion about whether their business or their health could stand this slip backward toward the elements. There also was puzzlement over just what the technical requirements of the Department of Energy regulations mean.

Although the most-discussed feature of the new rules has been the 78-degree maximum for thermostat settings, DOE officials point out that buildings may comply and save energy into several other ways, some of which may provide sub-78-degree office temperatures.

But most Washington buildings - especially old ones - are so energy inefficient, they say, that the thermostat on the wall is the most convenient regulator.

Even then, under the rules, the thermostat can be set anywhere provided the warmest room in the controlled area is no cooler than 78.

At Tysons Corner shopping center, normally a cool oasis in a desert of summer heat, temperatures yesterday varied from 79 degrees in lingerie at Woodward & Lothrop to 75 degrees in the television department and 80 degrees in the Hanover Shoe Store elsewhere in the mall.

"We used to have to wear winter clothes to keep warm in here," said Terri Tyler, a men's shop salesperson for Woodies. "Now, just to keep from fainting, you have to wear those cooler, silkier dresses."

On Capitol Hill, where some have termed hot-air production a major industry, temperatures hovered at 78 degrees in most buildings yesterday and the House suspended its coat-and-tie rule for reporters.

House Speaker Thomas P. (Tip) O'Neill's thermometer showed 77 degrees, and his office, like many others, had a cooling breeze from an electric fan.

Some hallways tended to the cooler - as low as 75 degrees. But in the office of Rep. Michael D. Barnes (D-Md.), typists turned off the lights for two hours to try to cool the place off.

One notable exception was the Library of Congress, where temperatures were reminiscent of the good old days (last week) of 74 and 75 degrees, with breezes caressing the stairwells. Their excuse: The library must protect valuable books, documents, films and musical instruments.

Secretary of Energy James Schlesinger was seating it out at 80 degrees in his office on the seventh floor of the Forrestal Building, where the windows are sealed shut. "We're all dying in here," moaned one DOE public affairs officer.

Meanwhile, the lobby of the DOE offices in Germantown, Md., gave no hint of a new thermostat requirement. As a receptionist and security guard discussed the president's speech of the night before, a thermometer on the wall read 7i degrees. It was positioned just six inches umder a color picture of President Carter. A second thermometer at the opposite end of the lobby registered 74 degrees.

The problem is the building, said building manager Melvin Harder, echoing number of other building managers. "It's impossible to keep all rooms at a constant temperature.

Several other DOE employes agreed, adding that they have been chilly in the A wing and are glad the thermostat temperature is being raised.

Supermarkets apparently were having trouble sorting out the various temperature requirements of frozen orange juice versus warm humans. At the Safeway at 600 S. Royal St., in Alexandria, thermostats over the frozen food freezer sections bore signs that said, "Must be set at 65 during open hours, 55 during closed. This is company policy."

Manager Jim Rich insisted that the store's thermostats were not set below 78 and added, "Usually people complain that it's too cold in here."

Giant stores, on the other hand, displayed signs saying, "It IS cold in here," and explaining that warming up the stores would actually require more, not less energy, because of the refrigerated food cases.

Other conscientious objectors in the war against waste included Barry Feavyear, manager of a Colorfax film store in Crystal City, whose thermostat was a few degrees under 78. The higher temperatures are not good for film, he said, "and besides the lady next door comlains about the heat. We're on the same system, so I keep it cooler for her." CAPTION: Picture 1, Portrait of President Carter, above, hangs in Energy Department building in Germantown over a thermostat that showed a reading of 72 degrees at 4:30 p.m. yesterday. Another thermometer in the same hallway registered 74 degrees. Photos by Tom Allen - The Washington Post; Picture 2, no capiton