Solar Panel Product Info

The number of panels depends on your energy usage, roof space, and panel wattage. A typical US home uses about 10,000 kWh per year, which usually requires 20-25 panels rated at 400W each. Use our Roof Solar Power Calculator to get a personalized estimate based on your location and energy consumption.

Modern residential solar panels typically range from 18% to 22% efficiency. Panels above 20% are considered high-efficiency. Premium brands like SunPower and REC offer panels exceeding 22%. Higher efficiency means more power per square foot of roof space, which matters most when roof area is limited.

Voc stands for Open Circuit Voltage, which is the maximum voltage a solar panel produces when no current is flowing (no load connected). This specification is critical when designing a solar array because your charge controller or inverter has a maximum input voltage. Exceeding it can damage equipment. Always check Voc when connecting panels in series.

Solar panel prices typically range from $0.25 to $1.00 per watt for the panel alone, depending on brand, efficiency, and where you buy. Budget panels start around $0.25-0.40/W, mid-range panels cost $0.40-0.70/W, and premium panels run $0.70-1.00/W. Use our price tracking tools above to compare current prices across retailers.

Top residential brands include SunPower (highest efficiency), REC (best warranty), Panasonic (excellent temperature performance), and Canadian Solar (best value). The best choice depends on your priorities: maximum power from limited space, long-term warranty coverage, or upfront cost savings.

Monocrystalline panels use single-crystal silicon cells and offer higher efficiency (19-22%) with a sleek black appearance. Polycrystalline panels use multi-crystal cells with slightly lower efficiency (15-18%) and a blue speckled look, but cost less. Most modern residential installations use monocrystalline panels because the efficiency gains outweigh the small price premium.

Solar panels typically last 25-30 years or more. Most manufacturers guarantee at least 80% of original power output after 25 years. Degradation rates average about 0.5% per year. The inverter usually needs replacement after 10-15 years, but the panels themselves continue producing power well beyond their warranty period.

Panel size depends on your application. For residential rooftop systems, standard 400W panels (roughly 6.5 x 3.5 feet) are most common. For RVs and boats, 100W-200W portable panels work well. For off-grid cabins, 300W-400W panels offer the best balance of power and handling. Use our Solar Panel Matcher to find panels that fit your specific requirements.