Which solar panel to choose?
Monocrystalline (Mono) vs Polycrystalline (Poly) is one of the most common questions we get asked. It is an important question to ask when deciding which panel technology is the best choice for the New Zealand conditions and your home.
The results from a NZ case study highlights that the Poly’s outperform the Mono’s based on per kW installed. The difference between a tier one Poly and Mono is somewhere between 4.5% – 7.7% more cost effective in NZ.
Not all solar panels are equal, the cost of a solar panel is determined in part by the size (in Watts), the physical size, the brand, quality of materials, the durability / longevity (or warranty period) and any certifications the solar panel might have. In addition to cost, when choosing the best solar panel for your installation situation, it is important to consider both how it is manufactured and what materials are used.
Three Tiered Manufacturers
There are three tiers of manufacturer quality, tier one products are the best choice for quality. Tier one includes the top 2 percent of solar PV manufacturers, SolarWorld and Canadian Solar are great examples. They are vertically integrated, which means they control each stage of the manufacturing process. These companies invest heavily in research and development, use advanced robotic processes and have been manufacturing solar panels for over 5 years. Tier one producers use the best grade of silicon to produce solar cells – the higher the silicon grade, the longer the solar cell will last and the better it will perform. Tier one manufacturers produce some of the best performing solar panels.
Tier two includes companies who invest less in research and development, are reliant on both robotic and manual work on production lines and have often been in solar panel manufacture for 2 – 5 years. Generally, Tier two manufacturers produce good panels at good prices.
Tier three encompasses 90% of new solar PV manufacturers. These companies assemble panels only, they usually don’t manufacture their own cells and don’t invest in research and development. While often available at a cheaper price, these manufacturers use human production lines for manual soldering of solar cells, which often isn’t the best approach as quality can vary operator to operator and day to day.
The major points you should bear in mind when buying solar panels aside from cost:
- Consider how the module is manufactured and the materials used.
- Research how the panels perform in real world situations – including positive tolerance, temperature co-efficient rating, PID and LID resistance and efficiency.
- Compare the warranty details of the solar panels you are considering buying.
- Learn more about the company that manufactures the modules
Solar Partners NZ source tier-one solar products from world leading manufacturers.