Installing rooftop solar panels, especially if you also add a home battery, is a massive investment. While I don’t think just focusing on return on investment all that helpful (there are non-tangible benefits to having solar panels and home energy storage solutions), it is one way to try to justify the expense…
And so here is mine. On this page, I hope to keep my savings on our electricity bill updated over time.
All figures are in NZD, and includes GST.
System Specifications
18 x Aiko Neostar 3 (490W) panels
1 x Tesla Powerwall 3 (13.5 kWh) battery
Mechanical switchboard timer (hot water)
Racking
Installation and electrical work
Total Cost: 31,175 (Feb-2026)
Summary of Savings
The “Savings” shown here is the monthly “Energy Value” as reported by the solar energy system. It is an estimate of the amount that we would otherwise have to pay the electricity company, if we didn’t have the system.
However, as you can imagine, our electricity usage might be a bit different if we didn’t have “free” energy from the sun, so this figure would naturally overstate our savings…
That said, utilising this “free” energy resulted in an improvement to the quality of life (we’re less stingy with heating, for example), so there are non-tangible benefits here.