First, we want to explain how tax credits work to clear up any potential confusion. A tax credit is a dollar-for-dollar reduction to the income tax you owe. For example, claiming a $5,000 federal tax credit will reduce your total federal income taxes due by $5,000.
https://www.reviewgeek.com/126589/what-you-need-to-know-about-the-federal-solar-tax-credit/