A bad solar installer can cost you tens of thousands in wasted money, system failures, and missed savings. Whether you're dealing with a shady contractor or just someone who cuts corners, spotting red flags early saves you from a nightmare installation. Here's what to watch for before you sign anything.
Lack of Proper Licensing and Credentials
A legitimate solar installer carries state and local electrical licenses, general contractor licenses (if required in your area), and industry certifications like NABCEP (North American Board of Certified Energy Practitioners). Ask for proof—literally get their license numbers and verify them with your state's licensing board. If they're vague or claim "we'll handle all that after you sign," walk away. Many states require specific solar training; an electrician alone isn't enough.
No Written Estimate or Contract
You should receive a detailed, itemized estimate before work begins. This should include panel specifications (brand, wattage, efficiency rating), inverter type, mounting hardware, labor costs, timeline, warranty details, and any permits they'll pull. If they give you a napkin sketch or a one-page generic quote, that's a red flag. A proper contract protects both of you and shows professionalism.
Unrealistic Promises About Savings
Watch out for installers claiming you'll cut your electricity bill by 100% or pay off the system in three years when your local sun conditions and usage don't support that. Honest installers will pull your actual utility bills, check your roof's sun exposure, and model realistic production numbers. Salvation often comes as 40–70% reductions depending on system size, location, and your consumption patterns. If the pitch sounds too good to be true, it is.
Pressuring You to Decide Quickly
High-pressure sales tactics—"this price is only good today," "we're leaving town tomorrow," "just sign here and we'll figure out details later"—are classic red flags. Quality installers respect that this is a major investment and give you time to compare quotes from multiple companies. Get at least three bids and take a week or two to review them. Mercoly helps you compare and find trusted solar panel installation providers in one place, making side-by-side evaluation easier.
Missing or Weak Insurance and Bonding
Ask for proof of general liability insurance (minimum $1 million), workers' compensation insurance, and a performance bond. Call the insurer to verify the policy is active—scammers sometimes show fake certificates. If they don't carry these, you could be liable if someone is injured on your property or if the work isn't completed.
Poor References or No Track Record
Request at least five recent customer references from similar residential installations. Call them and ask specific questions: Did the installer finish on time? Were there unexpected costs? Is the system performing as promised? Check Google reviews, the Better Business Bureau, and local contractor review sites. New installers can be solid, but at least three years of documented work is a safer bet.
Below-Market Pricing
If a quote is 20–30% cheaper than competitors, investigate why. Cut-rate installers often use lower-quality panels or inverters, skip proper permitting, rush installation, or underbid to lock you in and upsell later. Typical residential solar costs $2.50–$3.50 per watt before incentives (system size determines total). A 6 kW system typically runs $15,000–$21,000 before the federal tax credit.
Vague Warranty Language
Your panels should carry a 25-year manufacturer warranty covering defects. The inverter typically has a 10-year warranty (extendable to 15–25 years). The installer should also offer workmanship warranty (typically 5–10 years). If they can't explain what's covered, what isn't, and for how long, ask in writing and get answers before signing.
Unwillingness to Pull Permits
Permits exist for safety—your home's electrical system, roof load capacity, and fire code compliance all matter. Installers who say "we'll do it unpermitted to save you money" create liability nightmares and void insurance claims. Plus, your municipality likely requires it for incentives and solar rebates.
Frequently Asked Questions
Q: How long should a solar installation take? A residential system typically takes 2–5 days of actual labor spread over 1–3 weeks, including permitting, inspections, and utility interconnection. Delays beyond a month without explanation are a red flag.
Q: Should I finance through the installer or a bank? Installers often offer financing directly, but compare rates with your bank or credit union first. Some installers mark up loan terms—getting pre-approved elsewhere gives you negotiating power and a baseline for comparison.
Q: What questions should I ask about panel degradation? Ask about annual degradation rates (quality panels degrade 0.5–0.8% per year) and what the manufacturer guarantees by year 25. Anything above 0.8% annually is a warning sign of lower-quality equipment.
Spend time vetting your installer now—it pays off in a reliable, efficient system that actually delivers the savings you expect.