Section 25C let you write off up to $600 per year on qualifying replacement windows. That’s 30% of product cost, limited to ENERGY STAR Most Efficient models at your primary residence. Had windows installed in 2025? You can still claim this when you file your 2025 return.
Section 25C expired December 31, 2025. No federal window credit exists for 2026 installations or later. If your qualifying windows went in during 2025, the credit is still yours to claim on your 2025 return.
Who Qualifies for the Federal Tax Credit for Windows
Miss any single requirement and the IRS rejects your claim:
| Requirement | Specification | Why It Matters |
|---|---|---|
| U-factor | 0.20 or lower | Measures heat loss: lower is better |
| SHGC | 0.25 or lower | Measures solar heat gain: lower blocks more heat |
| Certification | ENERGY STAR Most Efficient | Standard ENERGY STAR alone doesn’t qualify |
| Manufacturer | IRS-registered with QMID | Required on your tax return since 2025 |
| Residence type | Primary home only | Rentals and second homes excluded |
| Installation deadline | By December 31, 2025 | Credit expired. 2026 installs don’t qualify |
One date oddity worth knowing: the IRS summary says “before December 31, 2025,” but the statute (26 USC 25C(i)) says “after December 31, 2025” does not qualify. December 31 itself is included under the statute, even though the IRS wording seems to exclude it.
Don’t confuse ENERGY STAR with ENERGY STAR Most Efficient. That mistake alone kills a claim. Standard ENERGY STAR certification isn’t enough. Confirm the Most Efficient designation before purchasing, or check your installed windows before filing.
How Much You Can Claim
You get 30% of product cost. Just the windows themselves, not labor, installation, delivery, or disposal. Two caps apply:
- Window/skylight cap: $600 per year
- Overall 25C cap: $3,200 per year (all eligible improvements combined)
Say you spend $8,000 total: $5,500 on products, $2,500 on installation. 30% of $5,500 is $1,650, but the $600 cap kicks in. You claim $600.
That $600 resets every tax year. If you replaced windows in 2023, 2024, and 2025, you could claim $600 each year with no lifetime limit. But the cap is per return, not per person. Married filing jointly? One $600 cap for the household, not $1,200.
Stacking matters too. A heat pump has its own $2,000 sub-cap. Windows get the $600. Insulation and doors share a $1,200 general bucket. Hit all three in one year and you’re at the $3,200 ceiling.
How to Claim: Form 5695 Step by Step
You need IRS Form 5695 , Part II (Energy Efficient Home Improvement Credit):
- Get your QMID/PIN codes first. Every qualifying window needs a manufacturer identification number. Purchase receipts usually have it; if not, call the manufacturer.
- Separate product from labor on your invoice. Only product cost counts. If your contractor gave you a lump sum, ask for a line-item breakdown now because you’ll need it.
- Fill out Part II of Form 5695. Enter window costs and QMID codes where the form instructions direct you. Windows and skylights have their own designated lines.
- Cap at $600. If 30% of your product costs exceeds $600, just enter $600.
- Transfer to your 1040. The credit goes on Schedule 3. Form 5695 prints the line references right on the form, so follow those.
Your 2025 return is due April 15, 2026 (October 15 with extension). Claim the credit for the year the windows were installed, not the year you paid.
Using TurboTax, H&R Block, or FreeTaxUSA? Look for “Energy Credits” or “Home Improvements” under deductions. Have your QMID codes and itemized invoices ready before you start. The software asks for them mid-flow, and scrambling for paperwork at that point is a waste of time.
Watch out: this credit is nonrefundable. It reduces what you owe, but it won’t produce a refund on its own. Total tax liability of $400? You get $400. The other $200 is gone. There’s no carry-forward either, so homeowners with a low tax bill in a given year often leave part of the credit unused.
Common Mistakes That Cost Homeowners Money
Over three tax years (2023–2025), the same handful of errors kept showing up on rejected claims:
Counting labor toward the credit. Only product cost qualifies. On a $12,000 window project, labor might eat $4,000–$5,000 of that total, leaving $7,000–$8,000 in qualifying expenses. Get an itemized invoice. If your contractor lumped everything together, call and ask for a split. Takes five minutes and could save your claim.
The QMID requirement blindsides people. For 2025 installations, the IRS demands manufacturer PIN/QMID codes on Form 5695. No code, no credit. The IRS rejects the form outright. Your installer should have provided these with your paperwork, but if not, the window manufacturer keeps records for every unit sold. Call them directly.
Assuming standard ENERGY STAR is enough. It isn’t. The credit requires the Most Efficient tier specifically: U-factor at or below 0.20, SHGC at or below 0.25. Standard ENERGY STAR minimums go as high as 0.30 in warmer climate zones, and a window meeting that bar won’t qualify.
Rental property? Second home? Neither qualifies. Primary residence only. Homeowners who split a project across their main home and a vacation house can only claim the portion installed at the primary address.
Wrong tax year on the return. The credit follows installation date, not purchase date. Windows ordered in December 2025 but installed in January 2026? They fall past the 25C cutoff entirely.
Timing and Strategy for Maximum Savings
Filing is the easy part. Maximizing the dollar amount takes a bit more thought.
Did you also install insulation, a new exterior door, or upgrade your HVAC in 2025? Each improvement has its own sub-limit under the $3,200 annual cap. A home energy audit flags which upgrades qualify. Bundling everything onto one return captures more of that $3,200 ceiling.
State incentives are separate from the federal credit and won’t reduce your 25C claim. Search your state energy office or the DSIRE database for local rebate programs still accepting applications.
Confirm your windows carry the Most Efficient designation, not just standard ENERGY STAR. Cross-reference the model number on the ENERGY STAR product finder or pull the manufacturer’s spec sheet. If the designation isn’t there, stop before you file; the IRS will catch it.
Looking ahead: as of April 2026, no federal window credit exists. Congress could reinstate one, but waiting on that is a gamble. Efficient windows save $100–$325 per year on energy bills depending on climate zone. Over 20 years, that return dwarfs a one-time $600 credit. Our window replacement planning guide covers budgeting and scheduling regardless of tax incentives.
For cost benchmarks and performance comparisons, see window replacement costs and window type comparisons .