As sub-freezing temperatures send heating bills soaring, more than 3,000 Northern Virginians are staying warm with the help of funds from the federal energy assistance program.

A total of $1 million is available in Northern Virginia from the federal Low-Income Energy Assistance Act of 1981.

Robert C. Osburn, information officer for the Virginia Department of Public Welfare, said that the state is running ahead of last year on applications for energy assistance. Last winter, the state aided 73,887 households. So far this winter, with two months of the program remaining, 82,233 applications have been approved.

But while applications are up, funds are down. Last year Virginia had $36 million to distribute. This year it is down to $26 million, Osburn said. Thus average benefits are expected to fall from $380 to $240.

If communities run out of money before the program ends March 31, Osburn said, there is $1.1 million available in a reserve fund.

The energy program provides persons and families with funds to help them pay their natural gas, electric, oil, kerosene, wood or coal bills. The one-time payments can be supplemented in emergencies.

Energy assistance payments in Northern Virginia range from $107 to $537 for oil, $51 to $255 for natural gas, $114 to $569 for kerosene, $82 to $413 for coal, $76 to $381 for wood, and $100 to $541 for electricity. These benefits represent a 32 percent reduction from last year.

The payments are based on a formula that takes into account the number of people in a household, household income level and the type of fuel used.

Under the terms of the federal energy program, states are required to seek out persons in need of assistance.

An elderly Loudoun county couple who use kerosene to heat their six-room house in rural Lincoln were given 175 gallons of kerosene by the county.

Lula Douglas, 72, a retired domestic and her husband Arthur, 69, a retired maintenance man, depend on a kerosene heater to heat their entire house.

Mrs. Douglas said this was the third year they have received energy assistance from Loudoun County.

"As long as I was able to work," she said, "I did not bother anybody and I had my tanks filled up. In the early fall , when the time came to turn them on, they were filled and paid for."

The 175 gallons of kerosene they received was worth about $240. She said she hoped the fuel would last at least two more months. She estimated she received about $200 from the energy program last year.

"This fall," Mrs. Douglas continued, "we got no kerosene from welfare until Nov. 6." In order to make it through the chilly fall, she called a daughter in Upper Marlboro, Md., who sent her money for fuel.

To be eligible for fuel assistance, householders must be receiving food stamps, welfare aid for dependent children, supplemental income under the Social Security Act or certain veterans benefits, or their income levels cannot exceeding 150 percent of the established poverty level or 60 percent of the median income for the state of Virginia.

Osburn said that Virginia residents who apply for energy assistance must take with them their latest fuel bill and prove that their maximum yearly household income has not exceeded:

$5,387 for one person; $8,172 for two people; $10,605 for three people; $12,675 for four people; $14,745 for five people; $16,815 for six people.

Allotments granted under the fuel program at this date are as follows:

Loudoun--Ronald Eamich, eligibility supervisor for the Loudoun County Department of Social Services, said last week that since the program began Nov. 1, 287 applications have been approved. Thus far, the county has used $85,620 of its $125,442 allocation.

Prince William--Rick Perez, a spokesman for the Prince William fuel assistance program, reported that the county has assisted 800 households and has spent $178,089 so far this year. An additional $20,000 has been donated by the county to add to the original grant of $260,994.

Fairfax--About 700 households in Fairfax have shared about $255,000 in energy funds, according to C. Edward Amundson of the county's fuel assistance program. He estimates his office processes more than 70 applications each week. The county's grant was $340,336.

Arlington--Douglas Smarte, of the Arlington County Division of Social Services, said the department has approved 711 households and has spent $122,000 so far this winter. The county's appropriation is $154,288.

Alexandria--Nelson Smith of Alexandria's Department of Social Services, said that the city has approved 553 applications and has spent $84,500 of its $125,442 allocation.

Northern Virginia residents can call the following numbers to find out how to apply for energy assistance:

Fairfax County, 591-3791; Arlington County, 558-2105; Loudoun County, 777-0577 or 471-6050, ext. 577; Prince William County (West), 369-9411, (East) 221-7101; Alexandria, 838-4290.

Washington Gas Co. advises customers having problems with their gas bills to call 750-1000. The company said that it can advise customers about energy assistance agencies and offer special payment plans for customers of all income levels.

All of the above Northern Virginia jurisdictions conduct outreach activities to ensure that eligible households, especially those with elderly or handicapped persons, are made aware of the energy assistance available. These activities include community programs, television and radio public service announcements, home visits to the elderly and invalids, publications and mailings to welfare recipients.