The lines that matter
Price per watt (total ÷ kW; shop $2.50–3.50), promised production with the model that produced it (kWh/kW/yr should land 1,100–1,600), equipment brand and warranty terms (inverter 10–25 years, panels 25-year performance), and the financing structure (owned vs PPA — it changes resale and who claims the tax credit).
The decoration
"Premium" panel brands with no price premium justification, production estimates without shading assumptions, and savings projections that assume retail export credits in markets that no longer pay them. None of these are lies, exactly — they are the optimistic setting of every dial.
The two-quote discipline
Get three quotes minimum; walk each through the payback calculator with identical inputs. The spread is usually 20–40% for the same outcome — and the median quote, not the cheapest, is often the one to interrogate hardest. The best quote shows its assumptions because it can afford to.