WASHINGTON — The nonpartisan Congressional Budget Office said Friday that repealing the Affordable Care Act would significantly increase federal budget deficits and the number of people who are uninsured.

But, it said, repealing the law would also raise economic output because it would create incentives for some people to work more.

The estimates came in the first major study issued by the new director of the budget office, Keith Hall. It was also the first report to use new methods of fiscal analysis, according to instructions from the Republican majority in both houses of Congress.

Repealing the law would increase federal budget deficits by $137 billion in the decade from 2016 to 2025, Mr. Hall said in the report. In addition, he said, the number of uninsured people, estimated at 35 million under current law, would increase by 24 million if the law was repealed.