“What are the most efficient solar panels?” is a question we get asked all the time here at Energy Informative. Homeowners constantly get hung up in conversion rates (efficiency) of solar panels, but what they really should be looking at is price.
Most homeowners will get along fine without the best performing solar panels on the market (unless their roof space is very limited). What are the best value solar panels?
Price per Watt
Solar panel prices are often listed as cost per watt ($/Watt). This is a useful measure when quickly comparing different solar panels, but is not the be-all end-all when determining the value of a complete solar system (more about this later).
The following table contains the ten cheapest solar panels from wholesalers and retailers on the Internet:
|#||Manufacturer||Model||Power (STC)||Price||Price per Watt|
These prices are based on bulk purchases of a minimum of 25 solar modules – about the size of a large residential solar system (5 – 6 kW). Add 10-20% to the price if purchasing on panel-by-panel basis.
Output is King
Instead of evaluating a solar system by its capacity in kilowatts (kW), get your solar advisor to quote how many kilowatt-hours (kWh) the solar system is expected to generate in its lifetime. Divide this number with the cost of the system.
You are now left with how much you are paying for every kWh of electricity the solar panels produce ($/kWh). Divide again by hundred to get cents/kWh.
If you`re just comparing two solar panels, and the length of their warranties is the same, doing the same analysis for the first year (as opposed to their lifetime) is usually good enough.
|Details||Solar System 1||Solar System 2|
|# of Solar Panels||28||28|
|Output (Year One)||8,930 kWh||9,066 kWh|
|Area||375 ft² (34.8 m²)||485 ft² (45.1 m²)|
System 2 is superior from a financial standpoint and most homeowners would choose it for this reason. System 1 is a good option for homeowners that lack roof space for a less efficient (but cheaper) solar system.
We generally see that the less efficient and cheaper solar panels tend to produce more electricity in a year for the same price as more expensive high-efficiency solar panels.
The Bottom Line
Any salesman will tell you that his solar panels are the best. Ask specifically for how many kilowatt-hours they will produce, divide by total costs (not panels or labor exclusively), and then compare to offers from other solar installers in your area.