Why a 6.6 kW solar system is the new ‘solar sweet spot’

Energy Matters - Australia

There’s no doubt about it, the average size of a solar power system is getting bigger.  Five years ago, most households were buying 3kW solar power systems (that’s approx. 12 panels).  Now, a 6.6kW solar system size is all the go (around 24 panels).

The big question is why?

There’s three main reasons:

  1. The cost of solar power systems keeps falling, making bigger systems more affordable.
  2. More panels = more STCs (the Federal Government’s ‘rebate’) = a bigger point of sale discount for you!
  3. 6kW is a great size for anyone thinking about adding a battery.
solar system size is largely limited by how many solar panels you can fit on your roof

Solar inverters are the brains of the solar operation, but panels like these are the workhorses.

But what about a 5kW solar system size?

A 5kW solar power system used to be all the rage.  But solar suppliers – and their customers – have done the maths and worked out that going 6.6kW can be better value.  And by 6.6kW, what I mean is that there’s 6.6kW of solar panels installed on the roof, with a 5kW inverter.

Is that solar system size allowed you ask?

Yes!  It is quite legitimate according to the Clean Energy Council guidelines as well as the network distributors (the companies that own the poles and lines).  The rule is that you are allowed to have your solar power system over-sized by 1.33%. This means that you can get an inverter with 5kW capacity and add 6.6kW of solar panels (5kW x 1.33% = 6.6kW).

Top benefits of a 6.6kW solar system size

  • You maximise the STCs without having to upgrade the inverter from 5kW to 6kW. This saves you a few hundred bucks. And most importantly – from a ‘value for money’ perspective – it lowers the cost/watt of your solar system.
  • 5kW inverters are not as expensive as 6kW inverters. Plus, there’s a much bigger range of 5kW single phase inverters on the market (more choice, lower prices).
  • Some network distributors – like Powercor, Ergon and AusNet – won’t allow more than a 5kW inverter (but they’re OK with you getting the panels oversized by up to 1.33% of the inverter’s capacity, i.e. 5kW x 1.33% = 6.6kW)
  • 6kW is a great size solar system for powering a battery (if you are thinking to the future, like that electric vehicle in your garage!)

Best value for your ‘solar dollar’

Overall, a solar system size of 6.6kW gives you more bang for your buck.  It is the new solar sweet spot for savvy householders looking to get the best value for their solar dollar.  Get a quote for one today!