Several groups of Northwest Washington homeowners are asking the city to change its nearly 20-year-old plan for replacing decorative street lights with less costly, sodium crime lights when city workers are ready to make the changeover in their neighborhood.

They say new technology offers a way to preserve the old ornamental tear-drop lights and convert them to brighter, energy-saving sodium lights. They say the conversion would cost the city less than what it is doing now: replacing the street lights in all but certain historic districts with high-pressure sodium cobra-head lights.

City officials say in 20 years they have replaced 42,000 steetlights with cobra heads and the savings already adds up to $2 million a year in energy costs.

Behind the push to change gears for the city's 8,000 remaining tear-drop lights is Barry Williams, a 12-year District resident who lives near Dupont Circle. Long interested in lighting, Williams at age 14 petitioned his St. Louis neighborhood to change a new mercury street light back to a bare-bulbed lamp like the others on his block.

He said he has always been interested in historic preservation and has sensed that many people don't like losing the tear-drop fixtures from their neighborhoods.

Last spring he visited Santa Monica, Calif., and noticed the city had many tear-drop lamps that gave off a soft, amber light, which meant they had been converted to sodium. Intrigued, he talked to officials there and learned that the technology now exists to preserve the old lights with sodium conversion kits.

When he came back, he said, he talked to District public works officials, but his idea "seemed to fall on deaf ears."

He then drew up a proposal and sent it to elected officials and Advisory Neighborhood Commissions in neighborhoods that still have lights to be changed. In two months, the ANCs in Chevy Chase, Cleveland Park, Woodley Park, Spring Valley, the Palisades, Forest Hills and the neighborhood around the U.S. Naval Observatory have all voted to ask the city to consider his plan.

This week, a spokesman for D.C. Council member John Ray (D-At Large) said Ray has written public works officials calling for a moratorium on street light replacements until the mayor can consider Williams's proposal and the department can study its costs.

Under Williams's plan, the city would convert the tear-drop lamps to low-sodium lights with conversion kits that cost less than the cobra heads. Low-sodium lights require less energy than high-sodium lights, which means they are less costly to operate. High-sodium lights are brighter, but Williams says that's exactly why they should not be placed in residential neighborhoods.

"High-pressure is very inappropriate for {neighborhoods with} single-family homes," he said. Low-pressure sodium "gives off a very soft light, it's not offensive and it doesn't keep people awake at night."

The plan has won the support of the city's Commission on Fine Arts, the American Council for an Energy Efficient Economy and officials at the U.S. Naval Observatory.

Observatory officials said high-pressure sodium lights in their neighborhood will add to light polution and hinder their astronomers' ability to see into the night sky. Low-pressure lights emit a monochromatic light that is easily filtered out, according to observatory astronomer Sean Urban.

But public works officials say Williams's proposal has problems. One is that although low-pressure lights are more efficient, they do not put out as much light and it is directed downward, said Traffic Engineer George Schoene. Cobra-head lamps shine light in a more elliptical and uniform pattern on the ground.

Schoene said many people consider the yellowish light from the low-sodium lights less attractive than the peach-tone light from the cobra heads. Some cities also have reported problems with people confusing them with yellow traffic lights, he said.

"If you put those lights in now, most people would say they are totally unacceptable," he said.

But Williams remains committed.

The old lights add character to the neighborhoods, Williams said. "We should do something before these teardrops are all destroyed," he said.