This example was generated using OpenSolar software and is provided as a guide only. Actual results will vary depending on the property, electricity usage, installation requirements, electricity tariff and household energy-use patterns.
The system modelling assumes panels installed at a 25-degree pitch and facing a 0-degree azimuth, which is north in New Zealand. The installation is assumed to be on a single-level property and does not include scaffolding or additional harness costs required for health and safety purposes.
Electricity pricing is based on MBIE average figures for New Zealand low-user and standard-user plans as at 15 February 2026. The modelling uses a daily charge of $2.07 per day including GST and a variable electricity charge of 31.2 cents per kWh including GST.
An export rate of 12 cents per kWh excluding GST has been used for electricity exported to the grid. Export rates are assumed to remain unchanged for the 25-year modelling period, with no inflation applied.
The household is assumed to consume approximately 8,000 kWh of electricity per year, equivalent to approximately 22 kWh per day. Solar self-consumption varies depending on the system and household energy-use patterns, but is estimated at approximately 44% to 45%. The remaining solar generation is assumed to be exported to the grid.
Projected energy costs assume electricity prices increase by 3.5% per year. The estimate considers current electricity costs, expected export credits, household electricity usage, and the position and orientation of the solar panels.
The return-on-investment calculation assumes that the Fronius inverter will be replaced once in year 15 of the system’s life. The replacement cost is assumed to be 50% of the inverter’s current replacement cost.
System performance assumptions include total system losses of 13.3%, inverter losses of 2.8%, optimiser losses of 0%, shading losses of 0%, and a performance adjustment of 0%. Output calculations use System Advisor Model 2020.02.29.r2. Panel orientation assumes 10 panels at an azimuth of 0 degrees and a slope of 25 degrees.
Electricity tariffs, export rates, daily charges, equipment prices and household electricity usage may change over time. You should contact your electricity retailer for current tariff information.
Estimates do not include replacement costs for other equipment that is not covered by warranty. Components may require maintenance or replacement after their warranty period. The system price excludes the installation of a retailer smart meter.
Please refer to the OpenSolar proposal disclaimer for additional information.