Aetna this week became the third insurer to submit proposed rates for new health plans offered later this year on Connecticut's public health exchange.

Aetna filed the suggested rates with regulators at the Connecticut Insurance Department on Thursday. Starting Oct. 1, individuals and small businesses will be able to shop an online marketplace, Access Health CT, for coverage during the 2014 calendar year.

The company is proposing individual health plans that will range in cost from $111 to $1,175 per year, with an average monthly premium of $363.56.

Aetna will offer high-deductible health insurance, called a catastrophic plan, which is typically attractive to young, healthy people who want to pay a lower monthly premium because they don't expect to have many medical expenses. It's sort of a just-in-case plan, and there are limitations under the Affordable Care Act about who may purchase such a plan.

Aetna also will offer plans that cover different percentages of a customer's total health care costs — factoring in how much a person pays in copays and deductibles. The percentage of cost coverage, called actuarial value, is measured by the federal government in categories named for precious medals: a bronze health plan covers 60 percent of a patient's costs, silver covers 70 percent, gold covers 80 percent, and platinum covers 90 percent.

Aetna's proposed average premium is $356 for a bronze plan, $487 for a silver plan and $477 for a gold plan. Prices will vary depending on where a person lives in Connecticut, whether the person uses tobacco and the person's age, among other factors.

The Affordable Care Act passed by Congress in March 2010 established health exchanges as a way to offer a competitive marketplace where individuals and small businesses may compare prices and shop for health plans. It's an optional place to buy coverage for those who don't have health insurance through an employer, a union or a government plan, such as Medicare, Medicaid or HUSKY.

Exchanges will be the only place that individuals and families who earn up to 400 percent of the federal poverty level — which is $44,680 for an individual or $92,200 for a family of four — may tap into federal subsidies to offset a portion of the cost of health insurance.

Last week, ConnectiCare submitted proposed rates to the state Insurance Department with a base rate of $397 per month for individual plans, which doesn't take into account adjustments for age and geographic area.

Two weeks ago, a new co-op called HealthyCT requested monthly prices ranging from $142 to $1,364 for individual plans, with an average price of $427.

"On the basis of our initial review, it appears that the Aetna submission is an attractive rate filing for consumers in Connecticut. … We are encouraged by the rates that have been submitted thus far and we believe they represent a positive outlook for consumers and small businesses in our state," said Kevin Counihan, CEO of Access Health CT.