GRADE - Make sure you do not end up with Grade C or lower
Grade A offers highest quality. Grade B panels usually have acceptable quality and could be much less costly than Grade A panels. Avoid grades lower than B.Check with your EPC if you are unsure of the panel grades.
EFFICIENCY - Higher the efficiency, you require less area for same output
Efficiency: 11%Area: 2.5m2 or 25.0 sq.ft
#For a 250W panel
Go for very high efficiencies only if you have significant space constraints
Look for module efficiency in the range 15-16%. Modules with efficiencies much higher could be quite expensive, and might not be needed unless you have significant space limitations
Warranty- Manufacturers offer two type of warranties; linear and standard. Guaranteed output is higher with linear than standard.This can result in generation increase of up to 7%
Going for Linear Warranty will cost you a bit more, but guarantees much higher yield than that for Standard Warranty. Go for it
TEMPERATURE COEFFICIENT - Panel performance decreases in high temperatures.
Consider panels with low temperature coefficient, else you can lose up to 2.5% of generation
(to vary panel temperature)
Go for low temperature coefficients so that panels perform well even at high temperatures
Anti-PID Feature - Panels without anti-PID(Potential Induced Degradation) may degrade easily and may need replacement within a few years
With Anti-PID feature, your panels are likely to last longer. Just make sure chosen panels have this feature.
LOW LIGHT PERFORMANCE - Good performance at low irradiance(sunlight) makes panels perform better in low light conditions.
Can result in a generation increase of up to 7%
If your region has low sunshine, ensure your panels have this feature
Poor panel selection could result in significant generation loss
Ensure the following at the very least in your panels:
And do these too: