Architects are going back to the drawing board to redesign commercial buildings and made them more energy efficient.

"We're having to relearn what was forgotten during 30 years of cheap energy," says David Meeker Jr., executive vice president of the American Institute of Architects.

Among the trends: greater use of natural light and other passive solar features, reduced interior lighting, changing in building facades (including more insulation and fewer windows) and a wide variety of other attempts to cut down on the need for the massive heating, ventilation and cooling in commercial buildings of the early 1970s.

"In some types of buildings 45 percent of the cost was going into mechanical systems to regulate the environment," Meeker said. And that's before any money is spent on the energy sources themselves.

Architects say much progress has been made, but add that much more is possible and necessary.

Architects have been about the only group involved in the building industry to push for quick implementation of the federal Energy Department's building energy performance standards, which would require specific levels of energy-efficiency. The group has gone so far as to take out a full-page newspaper advertisement urging Congress to implement the standards speedily, and saying that delay would amount to a "giant step backward."

A number of groups led by the National Association of Home Builders have charged that as currently written, the federal regulations would be unworkable and too costly.

But the architects say that 20 percent of the energy now consumed in the United States could be saved through more efficient buildings.

Mandatory standards will force the technology and innovation necessary to make buildings even more efficient, Meeker said.

The architects point to a number of buildings that show the new awareness of energy efficiency:

An existing IBM building in Chicago was fitted with a heat recovery system so that warmth created by lights, office equipment and people's bodies in interior offices is recycled to the colder windowed outer offices.

A shoe company in Brattleboro, Vt., is using a passive solar set-up to provide 38 percent of the winter heating needs of its warehouse. A large wall facing south has been painted black, and a double-thickness plastic sheet has been set in front of it. Heated air is trapped between the two, as in a greenhouse, and then vented naturally into the interior of the warehouse through ducts in the wall.

The Western Life Insurance Building in Woodbury, Minn., is designed to save $38,000 yearly in electric bills by reducing lighting in corridors and using bright lights only in individual work areas.

"We estimate that 80% of energy-efficiency gains can be achieved relative to lighting," says Meeker.

Many buildings are now being designed with as little as 60% of the lighting for work areas that was common in older buildings, and as little as 10% of the corridor lighting.

The Western Life Insurance building is windowless on its east and west sides to minimize summer heat, and has movable louvers on the south to shut out the hot summer sun.

Waste heat from the building's data processing unit is recovered and used in the building's heating system.

Architects say energy conservation features don't have to add much to a building's initial cost, and that later savings are significant.

The Georgia Power Co.'s new headquarters in Atlanta, scheduled for completion in December, is expected to consume 43% less energy than a conventional office building and be comparable in cost.

The south face of the 24-story tower is stepped, so that each floor slightly overhangs the floor beneath. The shade reduces the cooling load.

Rather than placing stairs and elevators in the center as in most areas" to the east and west sides of the building where they will serve as "thermal buffers," increasing insulation.

A computerized monitoring system for the building includes photoelectric cells which selectively turn off lighting circuits when they sense sufficient natural light.