Many federal workers could save from $200 to $500 a year in health insurance premiums if they had the time and energy to comparison-shop the 106 plans Uncle Sam offers them.

And they may be getting extra time this year to pick a health insurance plan for themselves and their families. Federal workers are now in the midst of an "open season" period, which ends Dec. 7, during which they can make changes in the 1980 health insurance. Experts say many government employes over-insure themselves or their families by buying "name brand" policies, or by automatically choosing the more expensive high options of plans when low-option coverage would normally suffice.

Federal workers could get a stretched out "open shopping season" if a U.S. District Court judge here agrees with a lawsuit brought by the American Federation of Government Employees. The union (which has its own health plan) says the government has played favorites this year, distributing thousands of brochures encouraging employes to buy specific plans. d

Health Education and Welfare printed the brochures. They compared benefits (but not rates) between the two biggest health carriers in the federal program, Blue Cross-Blue Shield, Aetna, and various health maintenance organization (HMO) plans offered in several big cities. This column first reported the HEW brochures, and the department's office of HMO information was flooded with calls from employes seeking more information.

The union says the brochures gave unfair advertising advantage to Aetna, Blue Cross-Blue Shield and the HMOs. It is demanding that the HEW brochures -- nearly 350,000 in the metro area -- be withdrawn, and that the "open season" be extended so employes can shop longer.

It is also asking the court to allow employes who have already picked 1980 health insurance during the on-going open season to be allowed to change again if they find a better insurance deal. The court will rule on the request next week.