Federal Solar Tax Credit & Battery Storage Estimator
Estimate your net out-of-pocket cost after the federal credit, your annual and lifetime energy savings, and how many years until the system pays for itself — then download a professional PDF report.
| Year | Annual Savings | Cumulative Savings | Net Position | Status |
|---|---|---|---|---|
| Calculate to see schedule | ||||
Highlighted rows show the years after the system has paid for itself (net position positive). Savings grow each year with the assumed utility rate increase.
The 30% residential credit ended with 2025. Under the One Big Beautiful Bill Act, the section 25D credit no longer applies to property placed in service after December 31, 2025, so an owned system installed in 2026 or later receives no federal residential credit. The 30% rate still applies to 2025 installs, and the separate section 48E credit still covers lease, PPA and commercial systems through 2027 — though there the company that owns the system claims it. Set the credit rate in the calculator to match your own situation.
How to use the solar and battery estimator
Enter what the system costs, what credit rate applies to your situation, and what you currently pay for electricity. The estimator returns your net cost after incentives, the year the savings finally overtake it, and a year-by-year schedule showing exactly where the crossover happens.
Enter system and battery cost
The installed price before incentives, with battery storage separate so you can see what it adds.
Set the credit rate
30% for a 2025 install, 0% for an owned 2026 system, or whatever rate actually applies to you.
Add your bill and offset
Your real monthly electric bill and the share of it the array will replace — be honest rather than optimistic.
Read the payback and save the PDF
Net cost, break-even year, lifetime savings, a net-position chart and a full year-by-year table.
How net cost and payback are built
Two halves. The credit and any rebates come off the gross price to give a net cost — the hole you start in. Then annual bill savings, growing each year with utility rates, fill that hole back in. The year the cumulative savings pass the net cost is your payback point, and everything after it is return.
Worked example — $22,000 of solar plus a $12,000 battery, 2025 install
Gross cost $34,000, credit at 30% → $10,200, net out-of-pocket $23,800
Year-1 savings: $180 × 12 × 90% = $1,944
Growing 3.5% a year, cumulative savings reach $23,800 during year 10.4
Over 25 years the bill savings total $75,719
Net savings of $51,919 across the period — a bit over twice what you put in. The last year alone saves $4,439, because the escalation that makes utility bills painful is exactly what makes the array valuable.
What actually moves the payback
Four levers, ranked by how much they matter. The baseline throughout is the calculator’s default: $22,000 of solar, a $12,000 battery, a $180 monthly bill at 90% offset, 3.5% annual rate increases and a 25-year horizon.
| Situation | Credit | Net cost | Payback | 25-yr net savings |
|---|---|---|---|---|
| 30% credit plus a $2,000 rebate | $10,200 | $21,800 | 9.6 yrs | $53,919 |
| 30% credit, 2025 install | $10,200 | $23,800 | 10.4 yrs | $51,919 |
| No credit, owned 2026 install | $0 | $34,000 | 13.9 yrs | $41,719 |
Losing the credit costs $10,200 and pushes the break-even out by three and a half years — but the system still pays for itself inside the analysis period. That is the honest read: the credit made solar attractive faster, it was never the only thing making the numbers work.
| Monthly bill | Year-1 savings | Payback | 25-yr savings | 25-yr net savings |
|---|---|---|---|---|
| $120 | $1,296 | 14.4 yrs | $50,479 | $26,679 |
| $180 | $1,944 | 10.4 yrs | $75,719 | $51,919 |
| $250 | $2,700 | 7.8 yrs | $105,165 | $81,365 |
| $350 | $3,780 | 5.8 yrs | $147,231 | $123,431 |
This is the biggest lever on the page. The size of your current bill decides almost everything, because it sets how fast the hole fills — a $350-a-month household breaks even in under six years on the identical system that takes a $120 household more than fourteen. Solar rewards heavy consumption in expensive markets, not modest bills in cheap ones.
| Annual rate increase | Payback | Year-25 savings | 25-yr savings | 25-yr net savings |
|---|---|---|---|---|
| 0% (flat rates) | 12.2 yrs | $1,944 | $48,600 | $24,800 |
| 2% | 11.1 yrs | $3,133 | $62,267 | $38,467 |
| 3.5% | 10.4 yrs | $4,439 | $75,719 | $51,919 |
| 5% | 9.8 yrs | $6,264 | $92,782 | $68,982 |
| 7% | 9.1 yrs | $10,079 | $122,956 | $99,156 |
Notice the split. Escalation barely moves the payback — three years of range across the whole span — but it quadruples the lifetime figure, because it compounds hardest in the years furthest out. Treat the payback number as fairly robust and the 25-year total as an assumption you should stress-test.
| Question | Answer |
|---|---|
| Does it qualify for the credit? | Yes — storage of 3 kWh or more qualified in its own right, even without solar attached. |
| Does it lower the bill here? | No. This model ties savings to bill offset, and the battery does not increase how much of your bill the array replaces. |
| Could it save money in reality? | Yes, on time-of-use rates, by storing cheap power and using it during expensive hours. That saving is outside this model. |
| What is it actually for? | Backup power through outages, and independence from the grid at night. Value that is real but does not show up as dollars saved. |
| What does it cost in payback? | In the default scenario, 3.3 years — 7.1 without the battery against 10.4 with it. |
If the battery is going in for resilience, judge it on resilience. Feeding it into a payback calculation makes an otherwise strong solar case look slower, because the estimator charges you for the battery without crediting the benefit you actually bought it for.
The shape is what matters more than any single number. You start deep in the hole, climb slowly while the savings are small, and then accelerate as utility rates rise — the curve gets steeper every year it runs.
- Most of the return lives in the back half — the second twelve years produce far more than the first, so a system sold before break-even may never repay what was spent on it.
- Compare the payback to how long you will stay — 10.4 years is a fine number for a forever home and a poor one if you are moving in five, unless the sale premium closes the gap.
- The curve ignores maintenance — inverters typically need replacing once in 25 years, and panel output declines slightly each year. Both push the real curve a little lower than this one.
Everything the estimator works out
One quote and one electric bill give you the net cost, the break-even year, the lifetime position and a schedule that shows the crossover year by year — plus a report to keep with the quote you are comparing it against.
The figures behind the payback
*From the worked example — $22,000 of solar and a $12,000 battery at a 30% credit, against a $180 monthly bill at 90% offset with 3.5% annual rate increases. Every figure recomputes for the numbers you enter.
Built for anyone weighing a solar quote
A solar proposal is easy to read optimistically. The point of running the numbers yourself is to see the net cost, the break-even year and the assumptions behind them separately, rather than as one confident headline.
Testing whether a proposal’s promised savings hold up against a realistic bill offset and an honest view of how long you will own the house.
- Compare quotes on net cost, not gross
- Check the offset assumption against your usage
- Confirm you can actually use the credit
Explaining to a buyer what an existing array is worth in monthly terms, and whether it comes free and clear or with a contract attached.
- Establish owned versus leased first
- Ask for the last twelve months of bills
- Note the system’s age against a 25-year life
Presenting a defensible payback that survives a customer’s own arithmetic, with the escalation and offset assumptions stated rather than buried.
- Show the assumptions, not just the total
- Separate battery cost from bill savings
- Attach the PDF schedule to the proposal
7 things to know before signing
The assumptions that quietly stretch a solar payback — and the questions that surface them before the contract is signed.
Solar tax credit and payback FAQ
The questions homeowners ask most when a solar proposal is sitting on the table and the numbers need checking.
The residential clean energy credit under IRC section 25D was worth 30% of the cost of a qualifying system, with no dollar cap. It applied to panels, inverters, wiring, mounting hardware, labor, permitting and qualifying battery storage.
It is a credit, not a rebate or a deduction. It reduces the federal tax you owe dollar for dollar when you file, rather than lowering the invoice your installer hands you.
For homeowners who own their system, yes. The One Big Beautiful Bill Act ended the section 25D credit for property placed in service after 31 December 2025, so an owned system installed in 2026 or later receives no federal residential credit.
Two things survive: the 30% rate still applies to systems placed in service during 2025, and the separate section 48E credit still covers lease, PPA and commercial systems through 2027 — though there the company that owns the system claims it.
Standalone storage of at least 3 kWh qualified in its own right, whether or not it was paired with solar — a change from earlier rules that required the battery to be charged by the array.
Worth separating in your head: a battery earns the credit but does not by itself lower your bill in a simple offset model. It buys backup power. On time-of-use rates it can also shift usage to cheaper hours, and that saving is not captured here.
The credit was nonrefundable, so it could only offset tax you actually owed and never produced a refund on its own. A $10,200 credit against a $4,000 tax bill did not send you a cheque for the difference.
Unused amounts carried forward to future tax years, so it was rarely lost outright — but it could take several years to absorb fully. That timing matters if you are borrowing against the credit to fund the system.
Take the net cost after credit and rebates, then count how long the growing annual savings take to add up to it. Year one is your monthly bill × 12 × the share solar replaces; each later year grows with the assumed rate increase.
The year cumulative savings pass the net cost is the payback point. On a $34,000 system with a $10,200 credit and a $180 bill at 90% offset, that lands at about year 10.4.
It depends on the type. A utility rebate for installing solar is generally treated as reducing what you paid, which lowers the amount the federal credit is calculated on. A state tax credit generally does not reduce the federal basis, though it can raise federal taxable income.
This estimator applies rebates after the credit rather than modelling that interaction, so with a large utility rebate, treat the credit figure as an upper bound and check the treatment with a tax professional.
Not for the homeowner. Under a lease or a power purchase agreement the solar company owns the equipment, so it claims the credit — often reflected in the rate it offers you rather than paid to you.
That is why ownership is the first question in any comparison. Cash and loan purchases put the credit in your hands; leases and PPAs put it in the installer’s and trade it for a lower upfront commitment.
Research generally finds a sale premium for homes with owned solar, though the size varies widely by market, system age and how much of the bill the array covers. It is not a reliable dollar-for-dollar recovery of what was spent.
Ownership is again the dividing line. An owned, paid-off system is an asset that transfers with the house. A leased system or an outstanding PPA is a contract the buyer has to assume, and it can complicate a sale rather than help it.
Estimation Only — Not Tax, Legal or Investment Advice: This estimator projects a net cost and a payback period from figures you enter and simplified assumptions. It does not model panel degradation, inverter replacement, maintenance, insurance, roof work, financing interest, net metering rules, time-of-use rates, battery cycling savings, or the effect of your actual tax position on whether the credit can be used in the year claimed. Bill savings depend on real system output, which varies with roof orientation, shading, weather, equipment and your future consumption; the offset percentage you enter is an assumption, not a measurement, and the utility escalation rate compounds any error in it across the whole horizon. The federal residential credit under IRC section 25D applied at 30% to property placed in service through 31 December 2025 and no longer applies to owned systems placed in service after that date; section 48E treatment of lease, PPA and commercial systems is separate and runs on its own timeline. State, local and utility incentives vary and may affect the federal credit basis. For planning purposes only; confirm system performance with your installer and any tax treatment with a qualified tax professional before making a decision.