Ask for the cash price. A low APR can hide a large fee added to the loan. Compare the cash price with the amount you would borrow.
What a dealer fee is
Many solar loans add a fee on top of the system's cash price. The installer receives the cash price and the lender keeps the fee, but you repay both, with interest. The Consumer Financial Protection Bureau found that these fees typically range from 10% to 30% of the cash price and can exceed 50%, and that the advertised APR often does not include them (CFPB, Issue Spotlight: Solar Financing, 2024). Lenders may call them program, platform, lending or finance fees.
In the CFPB's example, a system with a $30,000 cash price and a $9,000 fee becomes a $39,000 loan.
How the calculator works
- Amount you borrow: cash price × (1 + dealer fee).
- Monthly payment: a standard fixed-rate loan payment on that amount at the APR and term you enter.
- Extra you pay because of the fee: all your payments minus what the same loan would cost on the cash price alone.
- APR if the fee counted as interest: the rate at which your payments would repay only the cash price. Compare this number, not the advertised APR, with a loan from your bank or credit union.
How to find the fee
Ask the installer for the price if you pay in cash and compare it with the loan amount in your contract. If the loan amount is higher, the difference is the fee. Divide it by the cash price to get the percentage.
The calculator does not include the federal Residential Clean Energy Credit, which does not apply to systems placed in service after December 31, 2025. Be careful with any loan whose payment assumes you will pay down 30% with that credit.