Why These Questions Matter
Most solar sales pitches are designed to get you to a proposal quickly. The faster you get a quote, the harder it is to step back and evaluate whether the company — not just the price — is the right choice.
These 12 questions are designed to slow that process down in a productive way. A company that gives confident, specific answers to all of them is worth trusting. A company that struggles with a few of them is telling you something.
The 12 Questions
1. How do you assess whether my home is ready for solar?
What you're looking for: A company that evaluates your home's efficiency profile before sizing a system. They should be asking about your windows, HVAC, insulation, and utility bills — not just the size of your roof. If the answer is "we look at your bills and size the system," ask whether efficiency improvements were considered. A thorough company includes that conversation before the proposal.
2. How did you size this system?
What you're looking for: A clear explanation of the methodology — your usage history, any efficiency adjustments, planned load additions, and the production simulation tool used. Vague answers ("we sized it to cover your usage") aren't enough. Ask what tool they used, what inputs they entered, and what assumptions they made.
3. What panels and inverter do you recommend, and why?
What you're looking for: Specific brands and models, and a reason beyond "they're great panels." Ask about efficiency ratings, performance warranties, and why those components are the right fit for your roof and usage profile. If the answer changes based on what's currently in stock rather than what's best for your home, that's worth noting.
4. What warranties cover the panels, inverter, and workmanship?
What you're looking for: Specific terms for each warranty type. Panel product warranty (typically 10–12 years), panel performance warranty (typically 25 years with a minimum output guarantee), inverter warranty (varies by type), and workmanship warranty (labor and installation quality — this is the one that protects you if a roof leak develops 8 years from now). Vague warranty language is a red flag.
5. Who performs the installation — your own crew or a subcontractor?
What you're looking for: In-house installation is generally preferable for quality control and accountability. If installation is subcontracted, ask about the vetting process, who the subcontractor is, and how quality is managed. Some national companies subcontract heavily; local installers often use their own crews.
6. How long does permitting and interconnection typically take in my area?
What you're looking for: Realistic timelines based on local experience. Permitting timelines vary significantly by municipality in Illinois. Utility interconnection with ComEd typically adds 4–8 weeks after installation before the system is allowed to operate. An installer with local experience should have a realistic sense of timing in your area.
7. How do you handle roof penetrations, and does installation affect my roof warranty?
What you're looking for: A clear explanation of how roof penetrations are sealed and waterproofed, and an honest answer about roof warranty implications. Some roof warranties require that penetrations be made by the roofing manufacturer or a certified contractor — if that applies to your roof, ask how the installer handles it. If your roof is aging, ask their recommendation on timing before proceeding.
8. What Illinois incentives do I qualify for, and do you help with the paperwork?
What you're looking for: Knowledge of Illinois Shines (the SREC program) and ComEd rebates on applicable equipment, and confirmation that they handle enrollment and application on your behalf. Ask specifically about Illinois Shines — whether they submit the paperwork and how payments are structured.
9. What monitoring and ongoing support do you offer?
What you're looking for: Production monitoring that lets you verify your system is performing as expected, and clear support for issues that arise after installation. Ask how you'll be notified if your system underperforms, and who to call if there's a problem.
10. What happens to my system if your company goes out of business?
What you're looking for: An honest answer, not a defensive one. Solar companies do occasionally close. Panel manufacturer warranties survive the installer's existence; workmanship warranties do not. Ask what happens to your monitoring, service contracts, and workmanship warranty if the company is acquired, closed, or changes significantly.
11. Can you provide references from installations in my area?
What you're looking for: Real customers you can actually contact — not just a list of names. Ask for 2–3 customers with similar homes in your area, installed in the past 2–3 years. Call them. Ask about the installation process, communication, and whether the system is performing as promised.
12. Are there any additional costs I should plan for beyond the quoted price?
What you're looking for: A clear answer on what's included. Are permits included? Interconnection fees? Trenching, if applicable? Monitoring hardware? Critter guard or other add-ons? Getting a clear picture of total cost before signing prevents surprises after installation begins.
What SPM's Answers Look Like
SPM conducts a whole-home energy assessment before sizing any system. We use in-house installers for all projects. We handle all permitting, utility interconnection, and Illinois Shines paperwork. We offer a clearly stated workmanship warranty. And we base every system proposal on your home's specific energy profile — not a generic average.
If you want to run through these questions with us, start with a free assessment— we're happy to answer all of them.
Frequently Asked Questions
What if a solar company refuses to answer these questions?
That's a meaningful data point. A reputable company will be comfortable with direct questions about their process, equipment, warranties, and business stability. Avoidance, vague answers, or pressure to move to signing without answering your questions are red flags worth taking seriously.
Is it worth getting quotes from multiple companies?
Getting 2–3 quotes from reputable local installers is generally worthwhile. Use this question list with all of them. The goal isn't the lowest price — it's finding the company whose process, equipment, and warranty terms give you the most confidence in a 25-year investment. See our guide on comparing solar quotes for more on evaluating proposals side by side.