Prices for benchmark Obamacare insurance "silver" plans are set to drop an average of 0.8 percent next year in 16 major cities—while the lowest-cost "bronze" plans in those areas are looking at a 3.3 percent rise, a new analysis released Friday found.
The report by the Kaiser Family Foundation also suggests that because of variation in price changes, current customers should shop around to make sure they're getting the best possible deal before re-enrolling this winter.
Many people will be automatically re-enrolled in their current plan unless they select another one when enrollment resumes Nov. 15.
"You could end up paying more if your insurer is no longer offering one of the low-cost plans, so you should look carefully at your options," said Larry Levitt, Kaiser's senior VP.
Read MoreCourt voids Obamacare aid challenge
Still, Kaiser foundation president and CEO Drew Altman noted that overall 2015 premium prices are not dramatically higher than this year's.
"There is variation, but so far, premium increases in year two of the Affordable Care Act are generally modest," said Altman, whose foundation studied prices that would be paid by a 40-year-old nonsmoker in the 16 cities.
"Double-digit premium increases in this market were not uncommon in the past," he said.
The foundation also noted the federal budget will benefit from the average 0.8 percent decrease in prices of the second-lowest-cost "silver" plans, which are used to determine the amount of government subsidies received by all enrollees in a certain income range.
"If early trends hold and average premiums for the benchmark silver plans decline across the country, the federal government could end up paying out less than expected in tax credit subsidies overall for 2015," Kaiser said in a summary of the report. "Lower benchmark silver plan premiums would mean savings for taxpayers."
The health-care exchange plans' metal names—bronze, silver, gold and platinum—reflect both their relative prices and how much health expenses they cover.
Bronze plans, which cover about 60 percent of an enrollee's health expenses on average, are generally the least-expensive ones sold through the health-care marketplace. Silver plans, which cover about 70 percent of health expenses, are the second-least expensive.
The vast majority of the 8 million enrollees on the exchanges bought either a bronze or silver plans this year: 65 percent opted for silver and 20 percent chose bronze.
About 85 percent of enrollees received a discount on their monthly premiums because they were eligible for subsidies from the federal government due to their incomes.
The dollar value of those subsidies is linked to the price of the silver plan. Because of their importance to determining subsidies, benchmark plan prices are closely watched.
Kaiser's analysis compared the prices of the benchmark plans for this year to the prices of those plans for 2015. In some cases, the benchmark for 2015 is a different plan than for 2014 because of price changes by insurers.
The analysis found a relatively wide gap between price cuts and increases of benchmark plans.
In Denver, a 40-year-old nonsmoker who earns $30,000 annually is looking at a 15.6 percent price cut if he continues to buy the benchmark plan there next year. His Humana plan was the benchmark at $250 per month this year, but the benchmark plan next year will be issued by Colorado Health insurance Co-op, which is offering it at a price of $211 per month. The difference in premiums after a subsidy would be almost negligible: $209 in 2014, and $208 in 2015.
In Nashville, Tenn., the same person would be faced with a 8.7 percent increase in monthly premiums for the second-lowest-cost silver plan next year. Blue Cross/Blue Shield of Tennessee sold the benchmark plan this year for $188 per month, but next year, the benchmark would be sold by Community Health Alliance for $205.
That person would not be eligible for subsidies because the premiums in the region were set so low, Kaiser noted.
—By CNBC's Dan Mangan