What Solar Salespeople Don’t Tell You: My 6-Month Research Deep Dive
I’m a mechanical engineer. I spend my days analyzing tolerances, running failure mode analyses, and questioning every assumption in a spec sheet. So when I started getting solar quotes three years ago, I figured I’d be pretty hard to fool. I was wrong — or at least, I was almost wrong. It took me six months of research to fully understand the games being played, and by the end of it, I had a list of questions that made more than one salesperson visibly uncomfortable.
What follows is what I found. If you’re early in your solar research, this might save you tens of thousands of dollars. If you’re about to sign a contract, read every word before you do.
The Production Estimate Game
Every solar company will hand you a production estimate — a projection of how many kilowatt-hours your system will generate per year. This number is the foundation of every ROI claim they make, and it is almost always optimistic.
Here’s how it works: companies typically use software tools like PVWatts or Aurora to model production. These tools are legitimate, but they have inputs — and those inputs can be adjusted. The two biggest levers are system degradation rate and performance ratio. A conservative estimate uses a 0.5% annual degradation rate and a performance ratio around 0.75–0.80. Some companies quietly push degradation down to 0.3% and performance ratio up to 0.85 or higher. The difference over 25 years is enormous.
I asked every company I talked to for their PVWatts report or Aurora simulation file. Two refused entirely. Two others sent reports that, when I dug into the settings, had suspiciously optimistic parameters. Only one provided a model that matched industry-standard assumptions.
What to demand: Ask for the actual simulation report, not just the summary slide. Confirm the degradation rate, performance ratio, and weather data source they used. If they can’t or won’t provide this, walk away.
Shading: The Issue They Hope You Won’t Notice
Shade is the silent killer of solar production. Even a small shadow from a chimney, a neighboring tree, or a roof vent can dramatically reduce output — especially if your system doesn’t have module-level power electronics (microinverters or power optimizers).
Two of the five companies I got quotes from never mentioned shading at all, even though I have a 60-foot oak tree in my backyard that casts shadows across part of my roof from October through March. I only knew to ask because I’d done my homework. When I brought it up, one salesperson waved it off — “Oh, that won’t be a problem.” I asked him to run a shading analysis. He didn’t have the software open in front of him. He was guessing.
The industry standard tool for shading analysis is a solar pathfinder or lidar-based roof assessment. Some companies do this properly. Many don’t. If a company gives you a quote without performing a shading analysis and walking you through the results, they’re leaving a major variable unaddressed.
What to ask: “Can you show me the shading analysis for my roof? What percentage of annual production is lost to shading, and how did you account for it in the estimate?”
Oversizing: Whose Benefit Is It?
Here’s a counterintuitive one: bigger isn’t always better with solar, and a salesperson who pushes you toward a larger system may not be acting in your interest.
In Ohio, my utility (like many) has net metering rules that credit excess generation at a rate lower than retail. In some cases, you get wholesale rates for power you push to the grid — roughly $0.03–0.05 per kWh when you paid $0.13 to buy it. A system sized to produce significantly more than you use will generate credits you can’t meaningfully use, while the company pockets a larger sale.
I was quoted a 12 kW system by one company when my annual usage clearly supported a 8–9 kW system. I knew this because I’d already done my own calculation of how many solar panels I actually needed — a two-hour exercise that made overselling nearly impossible. When I asked why, the explanation was vague — “for future needs” and “EV charging someday.” Both might be legitimate, but I would have been giving away power at a loss.
Before I even started getting quotes, I went through twelve months of electric bills and used a Kill-A-Watt meter to profile my major appliances. Knowing my actual usage gave me a baseline no salesperson could argue with. That kind of data puts you in control of the conversation.
Warranty Language: The Fine Print That Matters
Solar warranties sound impressive in the pitch. “25-year panel warranty! 10-year workmanship warranty!” What they often don’t tell you:
- Panel warranties are manufacturer warranties, not installer warranties. If your installer goes out of business (and many do — solar company failure rates are high), you’re dealing directly with the panel manufacturer, who may also have gone out of business or been acquired.
- Workmanship warranties vary wildly. Read what’s actually covered. Roof penetration leaks? Panel replacement labor? Inverter replacement labor? Often these are excluded.
- Production guarantees are rare and conditional. Some companies advertise production guarantees but bury conditions that make them nearly impossible to collect on — specific monitoring requirements, notification windows, exclusions for weather variances.
- Inverter warranties don’t match panel warranties. Most string inverters carry 10–12 year warranties, but panels are warrantied for 25. Who’s paying for inverter replacement at year 15?
I spent two evenings reading through warranty documents. I used a checklist from a home energy audit guide I’d picked up early in my research — it had a solid section on solar contract review that helped me know what questions to ask. When I sent a written list of warranty clarification questions to three companies, only one answered all of them clearly. That was a significant signal.
What to demand in writing: Who is responsible for inverter replacement at year 12? What is the process if my installer goes out of business? What specific events void the workmanship warranty?
The “Today Only” Pressure Tactic
Every single company used some version of this. “This price is only good through end of month.” “We have a special incentive that expires Friday.” “We can only hold this install slot for 48 hours.”
In five months of getting quotes, not one of these deadlines was real. Every price held when I called back. Every “expiring” incentive was still available. These are textbook high-pressure sales tactics, and they work because solar is a complex purchase where people feel out of their depth and want to stop the research process.
My rule: I never made a decision the same day I received a quote. I told every salesperson upfront that I was talking to at least four companies and would make a decision over a 30-day window. That filter alone helped — the companies most invested in rushing me were, in every case, the ones with the weakest proposals on closer inspection.
What a Legitimate Quote Looks Like
After all of this, I did go solar — and I’m genuinely glad I did. The right company exists; you just have to know what to look for. Here’s my checklist for a legitimate quote:
- Provides full simulation report (PVWatts or equivalent) with all assumptions visible
- Performs and documents a shading analysis specific to your roof
- Sizes the system to your actual usage, with documented rationale for any oversizing
- Provides complete warranty documents before contract signing, not after
- Answers clarifying questions in writing without pressure or evasion
- Doesn’t use artificial urgency to push a signature
- Is licensed, insured, and has verifiable reviews and references
The six months I spent researching felt like a lot at the time. In retrospect, it was the best engineering project I ever ran. I knew exactly what I was buying, I paid a fair price, and I’ve had zero surprises. I’ve now published my actual solar ROI numbers after 14 months — real data vs. what the sales deck promised. That’s about the best outcome you can ask for on a $30,000 purchase.
If you’re just starting this process, take your time. Get the Kill-A-Watt meter, understand your actual usage, and read everything twice. The companies that want your business without educating you first are telling you something important about how they’ll treat you after the check clears.