Solar Loan vs. Cash: How Financing Changes Payback

The example home: what the system might save

To compare payment methods, you first need to know what the system saves. Here is the example home used across RoofPayback:

• A 7 kW system and 10500 kWh per year of electricity use.
• 40% of use happens while the sun is up.
• Installed cost of $3500 per kW ($24500 total), with no incentives.
• $100 per year in maintenance.
• Electricity prices rise 2.5% per year, and panels lose 0.5% of output per year.
• A 25-year horizon, with export credits capped at a year of grid purchases (an annual true-up).
• Production from PVWatts v8, south-facing at a 20° pitch with 14% losses, using one reference city per state. Prices are the EIA July 2026 residential averages.

Under those assumptions, the first-year savings and cash payback vary a lot by state:

State (city)	Year-1 savings, full credit	Payback, full credit
California (Los Angeles)	$3529	6.6 years
New York (New York City)	$2703	8.7 years
Texas (Houston)	$1580	14.3 years
Florida (Orlando)	$1578	14.1 years
Arizona (Phoenix)	$1615	13.6 years

Payback means how many years of savings it takes to earn back the cost of the system. These figures treat the $24500 as paid in cash. They do not include loan interest or dealer fees.

When monthly savings can cover a loan payment

A simple test is to compare your expected savings with the loan payment. Take the year-1 savings for your state, divide by 12, and compare it to a quoted monthly payment.

In the example home, Los Angeles has year-1 savings of $3529 and Houston has $1580. A given payment is much easier to cover in the first case than in the second. Higher electricity prices help, because every kilowatt-hour (kWh, the unit your utility bills you for) the panels produce replaces more expensive grid power. If you want to see how your local price compares, check the electricity prices page or your state page, such as Texas electricity prices.

Two cautions apply. First, savings from solar can change with your usage, your rate plan and your utility's export credit rules. See the guide on net metering vs. net billing payback. Second, a payment that is covered on paper in year one still has to be covered in the months when production is lower, such as winter. The guide on solar panels in winter by state explains that pattern.

Cash price changes the picture too

Installed price matters a great deal. The fact pack shows how payback moves with price per kW for three states:

State	$2500/kW ($17500)	$3000/kW ($21000)	$3500/kW ($24500)
Texas	10.7 years	12.5 years	14.3 years
California	4.9 years	5.8 years	6.6 years
Florida	10.5 years	12.3 years	14.1 years
Arizona	10.2 years	12 years	13.6 years
New York	6.4 years	7.5 years	8.7 years

A loan-financed price that is higher per watt pushes you toward the right-hand columns. Add interest, and your true cost moves further right again. That is why comparing a cash quote and a loan quote for the same system is worth the effort. Our solar payback period guide explains how payback is calculated.

No federal credit to lean on

The 30% federal Residential Clean Energy Credit (Section 25D) is not available for property placed in service after December 31, 2025, according to the IRS. Many buyers used to count on it to lower the net cost. With no credit, the installed price and financing costs matter even more. For more on this, read is solar worth it without the tax credit. State and utility programs differ, and DSIRE keeps a database of current ones. Check what applies to you before deciding.

Questions to ask before choosing a loan

• What is the cash price, and what is the loan price for the same system?
• What is the APR, and are there upfront or dealer fees?
• How long is the term, and is there a penalty for early payoff?
• What monthly savings does the installer expect, and what assumptions sit behind that number?
• How does my utility credit solar exports?

Use the loan option in the solar calculator to test different prices and terms. The methodology page lists the assumptions behind our numbers.

Bottom line

Cash is often cheaper because loan-financed systems had a higher median installed price ($4.7 per watt versus $3.5 per watt for cash) in Berkeley Lab's 2024 data, and interest comes on top. A loan can still work if your monthly savings cover the payment and you compare the cash and loan quotes carefully. Your own utility rates, quote and loan terms decide the answer. This article gives general information, not financial or tax advice.