Solar tool

Solar electricity systems (also known as photovoltaics, PV systems, or solar panels) convert sunlight into electricity, and are a form of renewable energy generation.

Before you get started

The solar tool helps you assess the estimated financial return of solar electricity for your house, based on a number of assumptions which can be found in your final report. It doesn’t factor in the other reasons you might want to install a solar system, such as energy resilience, environmental benefits or social responsibility. Please treat this tool as a guide to assist in your decision-making.

Your payback from solar (the time it will take you to recoup the upfront costs of the solar system from savings you make on your electricity bill) depends mainly on three important factors:

  1. The upfront installation cost you pay to have your solar system installed,
  2. The cost you pay per unit (kWh) for your electricity (variable charges) - note, the electricity market and variable charges could change over the lifetime of your system and affect your return, and
  3. The amount of electricity your household uses during the time of day when the sun is shining.

Batteries and high electricity use

This tool relies on average household electricity use profiles. It doesn’t take into account the costs and benefits of batteries, which can change the way you use (and the economics) of solar electricity. It also won’t take into account high daytime solar electricity use for things that use a lot of power, like EV charging, hot tubs, spa pools, and swimming pool heaters.

If you think you’ll install batteries with your solar system, or you use a lot of electricity during the day, please take this into account when using the tool. In these cases, we recommend consulting with a solar provider directly.

How to use the tool

You’ll be asked for your address and your electricity use, and the price you pay - so you'll need to have a recent electricity bill on hand. It will take you about 10-15 minutes to complete.

At the end, you'll get a detailed report estimating how much value you could get from solar.

So, grab your power bill and let’s get started.

This tool is brought to you by EECA.

Acknowledgement: This tool was developed by the EPECentre, University of Canterbury.

Visit for more information

Niwa colourThe solar tool incorporates solar data sourced from the National Institute of Water and Atmospheric Research (NIWA) through its SolarView service.

Read more