The federal Section 25C energy tax credits expired on December 31, 2025. The information below is provided for homeowners who completed qualifying work before that date and still need to claim credits on their tax return.
Under Section 25C of the tax code (as expanded by the Inflation Reduction Act), homeowners could claim a tax credit equal to 30% of the cost of qualifying energy-efficient home improvements completed through December 31, 2025. Unlike a deduction, a tax credit reduces your tax bill dollar-for-dollar.
If you completed qualifying work before the expiration, these were the annual limits:
These credits applied to the cost of materials and installation. No income limits. No phase-outs.
Federal tax credits could be claimed in addition to Efficiency Maine rebates. They were completely separate programs. Your Efficiency Maine rebate is deducted from your invoice upfront; your federal tax credit is claimed when you file your taxes. Together, they can offset 40–70% of your total project cost.
The $1,200 annual cap is shared across all "building envelope" improvements, including insulation, air sealing, doors, and windows. If you're only doing insulation and air sealing, you can use the full $1,200 for those projects.
Unlike Efficiency Maine rebates, federal tax credits are claimed on your annual tax return. Here's how it works.
Keep all invoices and receipts from your energy improvement project. We'll provide a detailed invoice that shows the qualifying equipment and installation costs.
When you file your taxes, complete IRS Form 5695 (Residential Energy Credits). This calculates your credit amount based on your qualifying expenses.
Transfer the credit amount from Form 5695 to your Form 1040. The credit reduces your tax liability dollar-for-dollar. It's not just a deduction.
The best part about federal tax credits? They stacked with Efficiency Maine rebates. These were two completely separate programs, so homeowners could take advantage of both on the same project.
That's a 50% reduction in your out-of-pocket cost. And for income-qualified households (under 60% AMI), the savings can be even greater, with Efficiency Maine covering up to $7,500 for a 3-zone system.
That's over 80% off the total cost. Weatherization projects for income-qualified households can sometimes be fully covered between state rebates and federal credits.