Before choosing a company
Questions to ask solar installers before you sign
A clear proposal should tell you who will do the work, what is included and who will help afterward. Use these questions to compare the answers from each company.
Open the interview checklist ↓
Solar installer interview checklist
Use one set of questions for every company. Record the answer, the document that supports it and any open item. A friendly sales conversation is useful, but it does not replace an agreed scope.
Who is responsible for my installation?
Ask for the contracting company's legal name and license number. Identify any subcontractors and the work they will perform. Keep the project manager's contact details alongside the sales contact.
The CPUC directs California consumers to check contractor and applicable salesperson registration details with CSLB. Match the record to the company on your agreement. See our California paperwork guide for the documents to review.
What changes after the site assessment?
Ask which quoted items are provisional: roof work, electrical upgrades, equipment locations or access. Who approves a change, how is its price documented and can a substituted model change the design? Use the roof planning checklist if roof work is unresolved.
What is included in the solar cash price?
Request equipment models, panel count, array DC capacity, labor, permitting work and exclusions. Ask for battery and other upgrade costs separately. Then use the solar quote comparison tool to compare like-for-like figures.
How was the production estimate calculated?
Ask for estimated annual kWh, the roof layout and the assumptions used for shade and system losses. Keep the forecast separate from an enforceable production guarantee. If a guarantee is offered, ask for its measurement period, exclusions and remedy in writing.
Who handles approvals and keeps me updated?
Request an owner and next update date for design, permit submission, installation, inspection and utility approval. Ask what happens if corrections are needed. Our solar installation process guide explains these milestones.
How to compare installer answers without a misleading score
For each question, mark the answer as documented, needs clarification or not included. Do not combine these into a star rating: a missing roof scope can matter more than several minor conveniences.
- Write the document name and page beside each answer.
- Send unresolved questions in one follow-up message.
- Ask for a revised proposal if the answer changes the price or scope.
- Compare the final versions, keeping dates and equipment models visible.
Example: one proposal includes electrical work; another calls it an allowance. Ask what the allowance covers and how a higher actual cost would be approved before treating the second price as cheaper. This is an illustrative comparison, not a price benchmark.
Use the itemized quote request template →What should I ask about solar warranties?
Keep equipment, installation workmanship, roof penetrations and any production commitment as separate entries. For each, request the provider, duration, exclusions, claim contact and which costs are covered.
- Who diagnoses a fault and pays for the visit?
- Are removal, shipping and reinstallation included in the written coverage?
- Who handles a roof leak near a mounting point?
- What documents and monitoring access should I keep?
Coverage depends on the actual agreement. The shared homeowner handover checklist helps organize documents and service contacts.
Source checked November 11, 2026: U.S. Department of Energy guidance on choosing an installer and the CPUC consumer guide. The comparison method and example above are CaSolar editorial tools, not installer ratings. Image is illustrative.
Check the proposed solar array size
Use the solar system size calculator to translate annual electricity use and a site-specific production assumption into kW and panel count. Keep the same array when comparing prices or battery options.