When purchasing photovoltaic panels, do not focus solely on the price tag. To ensure stable long-term power generation, extended product longevity, and higher overall returns, you must make a comprehensive selection based on various factors—including power generation efficiency, product quality, and the specific installation environment.
1. Conversion Efficiency
Conversion efficiency refers to a solar panel’s actual ability to convert sunlight into electrical energy. Currently, the industry-standard efficiency typically ranges between 18% and 23%. For commercial and industrial projects or large-scale power plants, it is recommended to select modules with an efficiency of 21% or higher; for residential rooftop solar systems, an efficiency of 20% or higher is generally sufficient for practical use. Given the same installation area, higher efficiency translates to greater power output and allows for more efficient utilization of installation space within the overall photovoltaic power system layout.
2. Cell Type
Monocrystalline silicon offers the best overall performance; it boasts high power generation efficiency and represents a mature technology. With a standard service life exceeding 25 years, it is suitable for a wide range of applications—including residential homes, factories, and large-scale power plants—making it the current mainstream choice in the market.
Polycrystalline silicon modules are lower in cost, but their power generation efficiency is generally moderate. They are best suited for simple projects with limited budgets where there are no exceptionally high demands regarding total power output.
Thin-film modules are lightweight and flexible, making them ideal for specialized installation scenarios such as curved architectural surfaces or vehicle-mounted equipment; however, their primary drawback is their relatively lower power generation efficiency.
3. Rated Power
Common solar panel power ratings currently available on the market typically include 450W, 550W, 600W, and higher. For residential rooftops and small-scale, distributed projects, selecting specifications in the 450W–550W range offers greater installation flexibility and adaptability. For industrial facilities and large-scale centralized power plants, priority should be given to high-power models ranging from 550W to 700W, as they deliver higher power output per unit area and generate greater overall returns.
4. Temperature Coefficient
In hot outdoor weather, photovoltaic panels inevitably experience varying degrees of power degradation. High-quality modules feature a stable temperature coefficient typically ranging from -0.30%/°C to -0.35%/°C, whereas inferior products commonly exceed -0.40%/°C. The lower the temperature coefficient value, the lower the power loss in high-temperature environments—a critical factor that demands particular attention in southern regions and areas subject to prolonged, intense sunlight.
5. Annual Degradation Rate
The rate at which a module degrades directly determines its power generation performance over the course of many subsequent years. High-quality photovoltaic panels exhibit a degradation of no more than 2% in the first year, with subsequent annual degradation kept within 0.5%. The more effectively degradation is controlled, the more stable the long-term power output remains, ultimately resulting in superior cost-effectiveness over the product’s lifespan.
6. Authoritative Certifications and Quality Credentials
Reliable photovoltaic panels undergo rigorous standardized testing; specific attention should be paid to compliance with IEC standards and credentials related to PID (Potential Induced Degradation) protection. Comprehensive certification serves as a vital guarantee for the product’s electrical insulation, lightning protection, resistance to outdoor aging, and long-term operational stability.
