Members of local congregations have been wearing less and perspiring more at weekly worship services this summer as churches and synagogues begin complying with federal energy guidelines.

"It's hot and sticky," said one pastor, "but they're grinning and bearing it."

Spiritual leaders at 25 churches synagogues and a mosque questioned in an informal sample survey said they have already adjusted their sanctuary and office thermostats to meet federal guidelines.

Despite the warmer temperatures, attendance at weekly services is not down, and according to several ministers, attendance is higher than usual for this time of year.

Members of Galilee United Methodist Church in Sterling, Va., have been keeping cool this summer by dressing more casually, according to church pastor, the Rev. Homer Hall. "I encourage them to come as you are. They're not wearing ties and jackets as much now," said Hall, "and I've even seen a few in shorts! But that's OK, I stopped wearing my robes when it got hotter, too."

Because Capitol Hill Presbyterian Church has never had air conditioning in the old church building, worshippers there resolved the heat problem long ago. "We keep cool with hand energy," said the pastor, the Rev. John Boyles. "We use hand fans and there's no problems."

In addition to minimizing air conditioning and lighting, the institutions have been implementing a myriad of energy saving ideas.

Berwyn Baptist Church in College Park is installing blown-in insulation in its aging building. And according to church pastor, the Rev. Leonard Johnson, the church is replacing its present high-wattage lighting with more energy-efficient fluorescent lighting.

The National Shrine of the Immaculate Conception, like several other churches, has reduced its Pepco bills by 5 to 10 percent already this summer by reducing esthetic lighting, according to William Brillo, assistant director in charge of building operations there. By reducing the heat producing lighting, the air conditioning unit does not have to work as hard, according to Brillo.

A number of other churches are holding services earlier in the day. "When the energy crunch began, we decided to change the time of our Sunday service from 11 a.m. to 10 a.m.," said Hall of Galilee United Methodist Church. "Because it's cooler then, we don't need to use the air conditioner as much," he said.

Worshippers at Sixth Presbyterian Church on 16th Street NW have not only been meeting an hour earlier on Sundays, they've been holding their services in their basement fellowship hall, according to the pastor, the Rev. Charles Summers. "It's so much easier to cool the hall than the huge sanctuary," said Summers. "I don't think a lot of people have been too happy about it, they like the sanctuary, but it's just too impractical."

Summers said his church will be donating the money saved on electricity to community project to feed the hungry.

Some other churches, like many homeowners are making use of simple techniques to save on energy costs.

Good Shepherd United Methodist Church in Silver Spring is seeking contracts on storm windows, which the pastor, the Rev. James Archibald, believes will greatly reduce heating costs this winter. "Our church is on the highest point in Montgomery County," said Archibald, "and we therefore are subject to harsh crosswinds that cause us to lose a lot of heat."

Other churches are turning down water heaters, or installing energy-efficient models.

Members of Paint Branch Unitarian Church in Adelphi hope that by recaulking their sanctuary and office windows, they'll save on energy. They are also rethinking scheduled major renovations to be sure they're practical in view of the new energy developments.

Other churches and synagogues, however, are concentrating on conserving fuel. Twenty-six members of Eastminister Presbyterian Church in Villa Heights, Md., are now traveling to Sunday services on a church bus that picks them up at their apartment buildings. "We've had that bus for about four years now," said the Rev. James L. Ewalt, church pastor, "but we just began using it for transportation to Sunday services in May."

Only a few members of his congregation used the bus at first, said Ewalt, but now the bus is picking up persons from six buildings.

Carpooling may be the wave of the future at St. Alban's Episcopal Church on Massachusetts Avenue NW. The church administration there recently asked members to fill out "transportation needs and resources" forms that can be used to match riders with drivers at several of their services and programs.

Metropolitan Memorial United Methodist Church on Nebraska Avenue NW will encourage car pooling and save electricity and fuel this fall by juggling a host of committee and council meetings into one night per month. Their rescheduling will save energy dollars by cutting back the number of nights the church building must be lighted and heated to accommodate the meetings.

In answer to the complaints of parents of religious school students, Congregration Olam Tikvah in Fairfax is opening a new satellite religious school this fall. According to Rabbi Itzhak Klirs, some parents have been driving their children over 20 miles three times a week to attend the after-school religious studies program at the synagogue.

This fall, however, the parents can drive their children to classes either in Reston or Fairfax.

The Rev. John L. Pharr, United Presbyterian Church clerk, said he has been pressuring the Presbyterian church administration to schedule their six meetings next year at churches that are located near metro stops. Pharr said he believes his nudge will work.