Solar panels come in a variety of configurations with the following key factors to consider:
- Kilowatt (kW) rating: This determines how much energy the panel will generate when the sun hits it. This rating is based on optimal peak performance and will vary depending on the number and quality of solar cells in the panel. Usually the higher the kW rating the larger the panel and the more cells it contains, although efficiency of solar panels available on the market has gotten incrementally better every year as manufacturers find new ways to increase solar cell efficiency. A good “tier one” panel will get somewhere between 19%-23% efficiency.
- Power Output warranty: Solar panels do lose efficiency slowly over time. That means their rated power output will change over their lifespan. The solar panel manufacturers will provide a warranty for this output range – usually at least 83% efficient from the date of manufacture after 20 years. It’s good to know what that guarantee is in the panel spec sheet before buying.
- Physical integrity warranty:
- Size and Colour:
- In-roof & on-roof: AS mentioned on our page about installation solar panels can be installed on a frame set a few centimetres proud of the roof or inset in a framing system that is set into the roof itself (usually done for newly built homes.) For in-roof systems there will more limited choice in panels since they must be compatible in size and fire-safety rating for the in-roof framing system. Usually this eliminates the larger kW rated panels since they are too big to fit those types of framing systems.
Tier 1 or Premium?: The difference here lies in the warranties provided. Tier 1 panels will be high quality panels with usually a 10-12 year warranty for structural integrity and 20 year power output warranty of minimum 83-85%. Premium panels will generally have a 25 year warranty for both with power output being guarantied to 90% or above during that period. This panels will usually be about twice the price of tier 1 panels so they perform best where the solar panel array will be very hard or expensive to reach (say at the top of a flat block) if there are any maintenance issues, and therefore their reliability justifies the price.