Rooftop solar can slash your electricity bill for 25 years — but only if the numbers work for YOUR roof and YOUR usage. Here is how to evaluate it like a skeptic.
The Real Cost Breakdown
Panels themselves are now the cheapest part of the system. What you pay for: panels (~25%), inverter (~15%), mounting and wiring (~20%), and labor/permits (~40%). That is why three quotes can differ by 30% for identical hardware — the margin lives in labor. Ask for itemized quotes and compare cost per watt, not just totals. Beware door-to-door "today only" pricing — it is almost always inflated.
Payback Math: Do It Yourself
Payback = total cost ÷ annual bill savings. Pull 12 months of electricity bills, multiply by your utility's rate trend (prices usually rise), and estimate generation from your roof's sun hours, not the brochure's. Typical payback in 2026: 6–10 years in sunny regions, longer where electricity is cheap or cloudy. Factor in available tax credits and net-metering rules — they can cut payback by years, but policies change, so verify current rules yourself.
Is Your Roof Suitable?
South-facing (north-facing in the southern hemisphere) roofs win. Heavy shading from trees or buildings can halve your output — a site survey should measure this, not guess. Roof age matters: if your roof needs replacing within 10 years, do the roof first — removing panels later costs thousands. Check structural load capacity and local HOA or heritage restrictions before signing anything.
Questions Installers Dread
Ask: What is the cost per watt, itemized? Which inverter brand and warranty (inverters fail before panels — 10-year minimum warranty)? What is the panel degradation rate (good panels lose ~0.5%/year)? Who handles permits and grid connection? What is the production guarantee in writing? Get everything in the contract — verbal promises about savings are worthless. Never pay 100% upfront; milestone payments protect you.
Smart start: get three itemized quotes, run your own payback math, and check your roof's age before any sales visit. Informed buyers get the best systems at the best prices.