DENVER – Under fire for his support of the Affordable Care Act, U.S. Sen. Mark Udall said President Obama’s landmark legislation isn’t perfect but has benefited Udall’s family.

During a visit to an energy conservation company Thursday, the Colorado Democrat said the law has allowed his 23-year-old daughter to stay on the family health plan. In addition, he said, he was happy with the coverage and savings he got by using the state health insurance exchange.

“The system we had before was broken,” he said, asserting that Colorado residents want the new law to work.

He is being hammered during the campaign over what critics call shortcomings in the new law. A $970,000 ad campaign by the conservative Americans for Prosperity contends that “Obamacare just doesn’t work” and urges viewers to “tell Sen. Udall to stop thinking about politics and start thinking about people.”

On Friday, the Democrat-aligned Senate Majority PAC announced it will spend $550,000 to air an ad countering that campaign. The PAC says the attacks come from insurance companies and out-of-state billionaires supporting Udall’s likely opponent, Republican Rep. Cory Gardner.

Gardner has his own personal story about the health-care law. Last fall he said his family’s insurance policy was cancelled because of the Affordable Care Act, and he had to buy more expensive insurance.

Colorado regulators say 335,000 residents received notices their health insurance plans were being cancelled and more than 90 percent were offered options to renew or join other plans.

More than 100,000 Coloradans have bought health insurance on the state exchange and about 150,000 have been added to Medicaid rolls under the Affordable Care Act.

Udall did not provide further details or documentation on his plan.

U.S. Sen. Mark Udall says his family has benefited from the Affordable Care Act.

The senator says the law is not perfect but does provide a net benefit. He supports fixing it rather than repealing it.