How much do solar panels cost?

Average 8 kW residential system: $20,000-$28,000 before incentives. After the 30% federal tax credit: $14,000-$19,600. Cost per watt: $2.50-$3.50 installed. The federal tax credit (30% through 2032) is the biggest cost reducer. Additional state incentives may further reduce the net cost.

Are solar panels worth it?

Yes for most homeowners with suitable roofs and average-to-high electricity rates. Solar panels typically pay for themselves in 6-12 years and continue producing free electricity for 25-30+ years. They increase home value by roughly the amount of the system cost. Factor in the 30% federal tax credit and any state incentives.

How many solar panels do I need?

The average U.S. home (10,000-12,000 kWh/year) needs a 6-10 kW system, which is 15-25 panels (at 400 watts each). The exact number depends on your electricity usage, roof orientation, shading, and local sun hours. A solar installer will design a system sized to your specific needs.

How long do solar panels last?

Solar panels are warrantied for 25-30 years and typically produce electricity for 30-40+ years. Panels degrade slowly, losing about 0.5% efficiency per year. After 25 years, most panels still produce 85-90% of their original output. Inverters typically last 10-15 years and may need replacement once during the panel lifespan.

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Home Improvement

Solar Panel Guide: Types, Sizing, Installation, Incentives & Costs

Lumberama Editorial Team, Renewable Energy & Home Improvement Specialists Jun 10, 2026 15 min read

Solar Panel Types

Monocrystalline

Made from a single continuous crystal of silicon. The most efficient type (20–23% efficiency), meaning they produce the most power per square foot. Black in color. The premium choice and the most popular for residential installations because they maximize power production on limited roof space.

Polycrystalline

Made from multiple silicon crystals melted together. Slightly less efficient (15–18%) and less expensive than monocrystalline. Blue-speckled appearance. A good budget option when roof space is abundant.

Thin-Film

A thin layer of photovoltaic material deposited on glass, metal, or plastic. Lowest efficiency (10–13%) but the cheapest to manufacture. Rarely used in residential rooftop installations due to low efficiency. Used in ground-mount arrays and commercial buildings where space is abundant.

System Sizing

Average U.S. home: Uses about 10,000–12,000 kWh per year. A 6–10 kW solar system typically covers 80–100% of this consumption.

Sizing formula: Annual kWh usage ÷ annual peak sun hours ÷ 365 ÷ system efficiency (0.80) = system size in kW. Peak sun hours vary by location (4–6 hours/day in most of the U.S.).

Panel count: A typical 400-watt panel produces about 1.5–2 kWh/day. A 8 kW system needs 20 panels (8,000W ÷ 400W). Each panel is roughly 3.5x5.5 feet, so 20 panels need about 385 sq ft of roof space.

Roof requirements: South-facing roof is ideal (maximum sun exposure). East and west-facing roofs produce 10–20% less. Minimal shading from trees, chimneys, or neighboring buildings. Roof should be in good condition with 15+ years of life remaining (don't install solar on a roof that needs replacement soon).

Installation Process

Site assessment: Solar installer evaluates your roof, shading, electrical panel, and energy usage. Provides system design and production estimate.

Permitting: The installer handles building permits, interconnection agreements with your utility, and HOA approvals if needed.

Installation: Takes 1–3 days for most residential systems. Mounting rails are attached to roof rafters, panels are secured to the rails, and wiring connects to an inverter and your electrical panel.

Inspection & activation: Local building inspector approves the installation. Utility installs a bidirectional meter. System is activated and begins producing power.

Incentives

Federal Investment Tax Credit (ITC): 30% of the total system cost as a federal income tax credit. This is the single largest incentive and applies to all residential solar installations through
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A $20,000 system receives a $6,000 tax credit.

State incentives: Many states offer additional rebates, tax credits, or performance payments. Check the DSIRE database (dsireusa.org) for your state's current incentives.

Net metering: Most utilities allow you to sell excess solar electricity back to the grid for credits on your bill. When your panels produce more than you use during the day, the excess flows to the grid. At night, you draw from the grid and use those credits. Net metering policies vary by state and utility.

Costs

Average residential system (8 kW): $20,000–$28,000 before incentives.

After 30% federal tax credit: $14,000–$19,600.

Cost per watt: $2.50–$3.50/watt (installed, before incentives).

Payback period: 6–12 years depending on electricity rates, sun exposure, and incentives.

Battery storage (optional): $10,000–$20,000 for a home battery system (Tesla Powerwall, Enphase IQ, etc.). Provides backup power during outages and stores excess solar for evening use.