With the doubling of home heating costs in the past year, surviving the winter has become a number one worry for many District residents.

Energy experts stress that the first line of defense in cutting heating bills is the weatherization of homes, especially in the District where there are thousands of old, drafty and uninsulated homes.

Several D.C. Government agencies and community groups have launched programs offering householders energy audits and advice on how to weatherize their homes, from simple steps like blocking air leakage around doors to insulating exterior walls and attics.

For people who meet low-income, guidelines, the United Planning Organization is coordinating a neighborhood program to perform weatherizing services.

According to Chuck Clinton, head of the D.C. office of planning development's energy unit, there is no financial assistance available now for those above the poverty guidelines. The thrust of the city's effort to help those above the guidelines is through awareness programs and workshops to teach them conservation methods they can perform themselves.

Taking any or all of the following basic steps will help reduce fuel bills:

Insulate exterior walls and the top floor of your home with six inches of insultating materials. This is the most expensive conservation method. Washington area contractors charge between $2,000 and $2,400 in insulate the outside walls and attic floors of the average six-room house with 2,700 square feet of living space. Expenses are tax deductible, and fuel cost saving could be as much as 30 percent.

Caulk and weatherstrip around doors and windows to save another 5 to 10 percent on your bill. Hold a candle close to each door and window; if the flame moves, you have air leaks which means a heat loss. Storm doors and windows help, but they cost more than $45 each.

Have your furnace system checked and cleaned to make sure it is working at peak efficiency.

Repair broken windows, doors that close improperly, cracks in walls and holes in floors and in the foundation.

The D.C. energy unit can send you pamphlets with dozens of tips on saving energy, from covering drafty floors with newspapers to tacking blankets over windows. The Residential Energy Conservation Guide for D.C. Citizens offers detailed steps for doing your own energy audit and weathering. The phone number is 727-1800.

The energy unit has also set up an emergency energy hotline to answer questions about home heating and to handle requests for emergency assistance. The hotline number is 628-3181.

The Anacostia Energy Alliance at 2027 Martin Luther King Ave. SE stresses the do-it-yourself approach to weatherizing. During November, the alliance will hold three workshops for the public on solar energy and installing a solar wall, on weathering doors and windows and on installing insulation. The fee for all three workshops is $8 and the number for times and dates of the workshops is 889-7932.

The energy alliance also sends five-member teams to perform free energy audits for residents of Southeast Washington. Within three weeks of the audit, householders get written reports with recommendation for weatherizing based on the team's observations and calculations made by computer.

The energy alliance does not do any weatherizing, but its staff is available to anyone for information and advice.

The Potomac Electric Power Co. performs on-site energy audits for $25 or free audits based on information consumers send to them on questionnaires available from Pepco. The reports make recommendations, estimate costs of weatherizing and indicate what savings will occur if recommendations are followed. The number at Pepco is 872-4631.

The United Planning Organization's assistance programs are aimed at the city's 80,000 poor and elderly, the groups that traditionally suffer most in winter. To date, UPO and its delegate agencies in the District have weatherized nearly 400 homes and expect to do another 1,200 in 1980.

UPO's service includes insulating weatherstripping, caulking and making repairs.

To qualify for the UPO program, a family of two must have an income of less that $5,625. A family of four must have an income of less than $8,375. Applicants can expect to wait at least four weeks before the services can be performed. For more information, call. Axel Dennis, UPO's energy coordinator, at 638-7300, extension 603.