Monthly loan payment
$0
- System cost before incentives
- —
- Amount financed
- —
- Estimated monthly bill saving (year 1)
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- Net monthly cost (+) or saving (−), year 1
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- Total interest over the loan
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- Simple payback (years)
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Illustrative only. Not an offer of credit, a quote or financial advice. Lenders and contractors set real prices and rates.
How to use the solar loan calculator
- System size and price per watt come from the installer's proposal. Installed prices commonly run roughly $2.50 to $4.00 per watt before incentives, varying by region, roof and equipment.
- Incentives: enter any federal tax credit, state rebate or utility incentive you've confirmed you qualify for. Federal solar tax credit rules changed recently; check current IRS guidance or ask a tax professional before counting on a credit.
- Loan terms: solar loans often run 10 to 25 years. Longer terms lower the payment below the bill saving but add interest.
- Bill and offset: your current bill and the share the installer's production estimate says the system covers. Net metering rules in your state decide how much of that offset you actually realise.
Reading the results
The useful line is net monthly cost or saving: the loan payment minus the bill saving. A negative number means the loan costs less than the power it replaces from month one; a positive number means you're paying more now for savings that arrive after the loan ends. Simple payback is how many years of savings (with your assumed utility rate increase) it takes to recover the net system cost. Both ignore maintenance, inverter replacement around year 10 to 15, and panel degradation of roughly half a percent a year.
Loan, lease or PPA?
A solar loan means you own the system and claim incentives yourself. Leases and power purchase agreements put ownership with a third party: little or nothing down, no maintenance, but you give up the incentives and the long-term value, and the contract transfers with the house. PACE financing, repaid through property taxes, is a third option in some states and is now subject to federal consumer-protection rules. Our solar financing page compares all three with example numbers.
What the calculator leaves out
- Net metering and time-of-use rate details, which can cut the realised offset well below the production estimate.
- Dealer fees built into "low APR" solar loans, which inflate the system price; ask for the cash price.
- Inverter replacement, roof condition (a roof near the end of its life should be replaced first; see roof financing), and panel degradation.
- Battery storage, which changes both cost and savings.
Frequently asked questions
How much is a solar loan payment?
An 8 kW system at $3.00 per watt is $24,000; with no incentives, over 15 years at 7.99% APR that's about $229 a month. Incentives and term change it substantially.
Is a solar loan worth it?
If the loan payment is below the bill saving from month one and you'll stay in the home for years, usually yes. If it isn't, the decision depends on utility rate increases and how long you'll stay.
What is a typical solar loan term?
Ten to twenty-five years. Longer terms lower the payment but add interest and often outlast the inverter.
Do solar loans have dealer fees?
Many low-APR solar loans carry a dealer fee that the installer builds into the system price. Ask for the cash price and compare total cost.
Should I replace my roof before going solar?
If the roof has less than 10 years left, usually yes; removing and reinstalling panels later is expensive. Roof and solar are often financed together.
Sources and further reading
Primary sources we rely on for this page. Program rules change, so check the source before you rely on a figure.