Aon Hewitt is rolling out a new health insurance exchange that will enable employers to offer workers a wide array of plans offered by participating insurers.

By using the exchange, employers will be relieved of the time and hassle of selecting health insurers and administering their plans while employees will have a greater choice of plans. The first policies will be effective Jan. 1.

“There is a lot of work employers no longer will have to do,” said Mike Christie, senior vice president-exchanges with Aon Hewitt in Lincolnshire, Ill.

In all, employees will be able to choose from five different health care plans, including consumer-driven health care plans. Plans will be provided by nine insurers, including UnitedHealthcare, Cigna Corp. and Health Care Service Corp., which operates Blue Cross/Blue Shield plans.

Initially, premiums will be based on an employer's claims experience.

Aon Hewitt expects that more than 100,000 employees — including U.S. employees of parent company Aon P.L.C., Sears Holding Corp. of Hoffman Estates, Ill., and Darden Restaurants Inc., an Orlando, Fla.-based restaurant chain — will select and enroll in plans offered through the exchange this fall.

The exchange model deploys a defined contribution approach in which employers agree to provide a fixed premium contribution, with employees paying more or less depending on the level of coverage they choose.

The role of the employer, Aon Hewitt executives note, will be basic: deciding how much of the premium it will pay for each option, with insurers handling the processing of claims.

Aon Hewitt, which will assist employees with questions they have about the plans offered, will be compensated by fees and commissions paid by insurers that participate in the program.

While the health care coverage will be offered through an exchange, employers still will be plan sponsors. As a result, their premium contributions will be tax-deductible, while employees will be able to pay their share of the premium on a pretax basis.