Hiring the wrong solar installer can cost you thousands in inefficient systems, poor craftsmanship, and warranty headaches. Before signing any contract, you need to ask the right questions—ones that reveal whether a company actually knows your roof, your electrical setup, and your long-term savings potential. Here's what separates a solid solar installation from a costly mistake.
License and Insurance Verification
Ask to see current licensing documentation specific to your state. Solar installation typically requires a general contractor license, electrical license, or both, depending on where you live. Request proof of general liability insurance (usually $1–2 million minimum) and workers' compensation coverage. A reputable installer won't hesitate to provide this—it's basic due diligence that protects you if someone gets injured on your property or if equipment is damaged during installation.
Also ask about any outstanding complaints filed with your state's licensing board or the Better Business Bureau. A few minor complaints are normal for established companies, but a pattern suggests systemic problems.
Site Assessment and System Design
Find out whether the company offers a free, in-person roof inspection. They should physically visit your home to assess:
- Roof age, condition, and material (asphalt shingles, metal, tile, etc.)
- Roof orientation and shading from trees or nearby structures
- Electrical panel capacity and upgrade requirements
- Local permitting and utility interconnection specifics
Ask them to walk you through the proposed system design. What size array (in kW) are they recommending, and why? How many panels, what brand, and what wattage per panel? Request a detailed shading analysis—this directly impacts energy production. If they sketch the design on a napkin and call it a day, keep looking.
Warranty Coverage and Duration
Solar panels typically come with 25-year manufacturer warranties covering defects, guaranteeing 80% output after 25 years. But ask specifically:
- What does the equipment warranty cover (panels, inverter, racking, wiring)?
- What's the warranty period on the inverter? (Usually 10–15 years; many need replacement mid-way through system life.)
- Does the installer offer a workmanship or installation warranty? (Standard is 5–10 years.)
- Who handles warranty claims—the manufacturer or the installer?
A solid installer backs their work with at least a 10-year workmanship warranty. If they won't commit to that in writing, that's a red flag.
Timeline and Installation Process
Ask for a realistic project timeline from contract signing to final inspection and grid connection. Most residential systems take 3–8 weeks, depending on permitting. Request specifics:
- How long for permits in your jurisdiction?
- What's the actual installation day count?
- Will they handle utility interconnection paperwork, or is that your responsibility?
- What happens if weather delays work?
Also clarify who obtains the final electrical inspection and Permission to Operate from your utility. Some installers include this; others pass it to you.
Financing and Payment Structure
Ask about available financing options: cash, loans, leases, or power purchase agreements (PPAs). Understand the full cost breakdown:
- System cost (before incentives)
- Labor and installation fees
- Permitting and inspection costs
- Any equipment upgrades (electrical panel, roof repairs)
Request a breakdown of available incentives—federal tax credits (currently 30%), state rebates, and utility incentives specific to your area. A professional installer should clearly show how incentives reduce your out-of-pocket cost. Be wary of extremely low quotes; they often indicate corner-cutting or hidden fees later.
References and Past Work
Ask for at least three recent client references (installations completed in the last 12–18 months in your region). Actually call them. Ask about reliability, workmanship quality, and whether the system performed as promised. Request to see photos of finished installations similar to your roof type and home size.
Performance Monitoring and Support
Ask what monitoring system they provide and whether you can track energy production in real-time via app or web portal. Clarify the post-installation support: who responds if the system underperforms or equipment fails? Will they troubleshoot remotely, or do they charge for service calls?
Comparing multiple quotes side-by-side is critical—Mercoly helps you find and compare trusted solar installation providers in one place, so you can evaluate offers without endless phone calls.
Frequently Asked Questions
Q: How much does a typical residential solar installation cost? Most 6–8 kW systems range from $15,000–$25,000 before the 30% federal tax credit, translating to roughly $2.50–$3.50 per watt after incentives.
Q: Can I install solar if my roof is old or has shade? Older roofs may need replacement before installation ($5,000–$15,000), and significant shade can reduce system efficiency by 20–50%, so an honest shading analysis is essential.
Q: How long until solar "pays for itself"? Most systems break even in 6–12 years depending on local electricity rates, system size, and available incentives, then generate free power for decades.
Get free quotes from vetted installers today.