How many panels are needed for a 5kw solar system?

Back in 2015 this was an easy question to answer as a rule of thumb for every 1kw of solar panels you would install 4 panels at 250 watts each. Therefor a 5kw solar system would require 20 solar panels. This is still a good concept and rule of thumb. The main different now though is that solar panels are more efficient and can range from 250 watt solar panels still although not many in the market all the way up to an excess of 320 watts. This can change the number of panels required, If you your using a 320 watt solar panel you would only require 16 panels for a 5kw solar system.