THE SHORT ANSWER
Put proposals on the same footing: the same equipment scope, system size, roof work, payment structure, and production assumptions. A low monthly payment is only one part of the comparison.
A defined scope
Look for the equipment and materials, the included work, and the exclusions. Ask how hidden conditions or requested changes will be priced and approved.
A complete price
Separate the installation price from financing charges. Understand deposits, milestone payments, and any optional work. Compare the same scope between quotes.
A practical sequence
Ask who handles design, permits, inspections, and any utility requirements. Milestones help explain progress; dates dependent on outside approvals should be identified.
Ownership and support
Know who owns the equipment, who services it, and which warranties cover equipment and workmanship. Ask what documents and training are provided at handoff.
Turn the conversation into a plan
Create a side-by-side list and mark anything missing as “not specified,” rather than assuming it is included. Record the cash price separately from any financed amount. Ask what happens if the site visit identifies panel work, a roof repair, or a longer wiring route. Read the documents governing changes, cancellation, service, and any transfer if you sell the home. Take time to resolve conflicting answers in writing before committing to a project.
DOE recommends reviewing installer credentials, experience, roof conditions, communication, and comparable quotes. Further reading: U.S. Department of Energy: choosing a solar installer.
Questions for your project
- Match system capacity and equipment models.
- Separate cash price from financing terms.
- Ask who performs and supervises each part of the work.
- Record exclusions and the change-approval process.
Make it specific to your home.
Have an existing quote? Include it with your request so the scope can be discussed.