Federal workers and retirees can save $800 or more next year in health insurance premiums, and still buy adequate medical, dental and hospital protection, if they shop carefully during the Nov. 22-Dec. 10 insurance open enrollment season.

Premiums in the health program that covers 9.2 million people nationwide, and about half the population of metro Washington, are going up an average 24 percent in January.

Most workers/retirees here are eligible for between 16 and 26 of the plans. Possible choices range from nationwide giants, such as Blue Cross-Blue Shield and Aetna, to local HMOs (health maintenance organizations) and union-backed plans. Some of them require nonmembers to pay a special fee.

Picking the best plan is a nightmare.

But because premiums have become so high (workers can easily pay $1,400 in premiums next year) and because benefits offered by carriers vary, it pays to shop around, and shop carefully. Things to consider include what you can afford to pay, your family size, age (do you want braces, maternity benefits or orthopedic shoes?) and medical condition.

There is only one person -- you -- who can decide which plan is "best."

But there are some shopping hints. The best one is a 58-page blue booklet, "Checkbook's Guide to 1983 Health Insurance Plans" written especially for government types. It costs $3.95 and could save you a lot of money and heartache. Checkbook's number is 347-9612.

The guide breaks down health plans costs by premium, unreimbursed bills and benefits offered. It also provides guidelines for singles, and for families of various size. And also shows likely total costs for white-collar workers and retirees, with separate breakdowns for postal workers. And it shows your likely costs, by plan, depending on how high your actual medical bills may be.

The example we have chosen from the guidebook covers a family of three. It assumes that the insurance-holder is either a white-collar civil servant or retiree. It shows the Checkbook "average" cost-to-you estimate. That includes premiums and any required union fee, and also likely out-of-pocket costs for unreimbursed expenses. It also shows your cost if you have "high" ($23,000) medical bills next year.

Bear in mind this is for guidance only. Plans listed below are those generally available to people in this area. You will want more details on benefits, and need to match them up with your personal insurance needs.

Government Employees Health Association, average cost to you $1,300 a year, ranging up to $3,560 cost to you if your medical bills hit the $23,000 range.

Blue Cross-Blue Shield low option, average cost $1,350 with the "high" cost to you $4,620.

Kaiser-Georgetown, $1,370 up to $2,960.

Columbia Medical Plan, $1,430 ranging to $3,070.

Mail Handlers low option, $1,450 to $5,110.

Mail Handlers high option, $1,460 to $4,610.

Maryland IPA, $1,490 to $3,250.

Postal Supervisors, $1,530 to $3,360.

Group Health, low option, $1,600 to $3,810.

American Federation of Government Employees, $1,690 to $4,070.

Foreign Service plan, $1,740 to $3,540.

George Washington plan, $1,750 to $2,860.

Group Health, high option, $1,850 to $3,270.

Postmasters low option, $1,860 to $10,510.

Aetna low option, $1,870 to $7,670.

National Association of Letter Carriers, $1,870 to $3,010.

Aetna, high option, $1,880 to $6,270.

National Federation of Federal Employees, $1,910 to $3,240.

National Alliance of Postal-Federal Employees, $1,930 to $3,660.

American Postal Workers Union, $1,960 to $4,030.

National Association of Government Employees, $2,050 to $3,420.

National Treasury Employees Union, $2,120 to $4,300.

HealthPlus, $2,200 to $4,410.

Blue Cross, high option, $2,320 to $4,870.

Postmasters high option, $2,370 to $3,570.

The government is supposed to supply benefit and cost-comparison charts to employes at the office, plus a copy of the brochure for their current health plan. They will not "rank" plans, nor take into account such features as out-of-pocket costs, and costs for extra heavy medical bills.

Shop carefully this year.