How many panels are in a 6.6kW system?

As solar technology has progressed, panels have become both more efficient in terms of space and physically bigger. Rated output has risen to a point where panels are around half a kilowatt per module.

As of late 2024, leading panels are commonly 470 watts each, and around 2.1m² so for this size;

14 panels are needed to make up a 6.6kW system

They will cover at least 29½ m² with an area efficiency of approximately 223watts per square metre.

For context, a system sold by Solar Shop around 2008 may have used "thin film" panels which were rated at only 60 watts and 1m² in size. Systems were commonly only 1kW in total and used 16 panels. A 6.6kW system was almost unheard of and would require 110 panels.

The simple number of panels isn't a good measure of system size or efficiency.