Residential solar systems typically cost $2.50–$4.00 per watt installed before incentives. A 7kW system — enough for most US households — runs $17,500–$28,000 installed, coming down to $13,000–$21,000 after the 30% federal ITC. Commercial systems and ground mounts follow different economics. This calculator breaks costs into equipment, labor, permitting, and margin.
Tier-1 solar panels: $0.30–$0.55/watt. String inverter for a 7kW system: $1,200–$2,000. Microinverters (Enphase): $180–$250 per panel. Roof racking: $0.15–$0.25/watt. Battery storage (10kWh): $8,000–$14,000 installed. Equipment typically represents 55–65% of a residential solar project cost.
Rooftop residential system (7kW, standard pitch): 16–28 labor hours for a 2-man crew including racking, wiring, inverter, and interconnection. Difficult roofs (tile, steep pitch, complex layout) add 30–50% to labor time. Commercial ground mounts are faster per watt once the racking is set. Labor typically runs $25–$45/hr per installer plus a licensed electrician for interconnection.
Solar permits are required in every jurisdiction. AHJ (Authority Having Jurisdiction) fees: $150–$500 for residential. Utility interconnection application: $100–$500 depending on utility. Interconnection timeline can run 4–12 weeks — factor this into your project schedule and cash flow. Include permit expediting as a line item for customers who want faster turn.
The federal ITC (Investment Tax Credit) is 30% through 2032. Many states offer additional credits or rebates. SREC markets in states like NJ, MA, and PA add ongoing revenue for system owners. Your quote should show pre- and post-incentive pricing clearly — customers make buying decisions based on the net number.