i am your guide to solar finance

Find out how much can you save

A solar calculator will help you understand your options before you approach solar retailers and financiers.

A number of websites host solar calculators that are free and offer different types and degrees of analysis.

Solar calculators are not a substitute for detailed solar design or expert financial advice. Your accountant or financial advisor is the best person to advise you on solar finance options.

How to calculate your savings

To save money, the cost of the system including maintenance and finance needs to be less than the savings on your energy bill. There are two ways you can measure this.

Net bill savings

Compare the total cost of the solar system and the finance option (including upfront costs, maintenance and finance payments) with the total energy bill savings over the system’s life. Ask the solar retailer to give you the system’s net bill savings for all the payment options you are considering.

Cost per unit of energy

Electricity is sold in units called kilowatt hours (kWh) at a dollar per kilowatt hour price ($/kWh).

Compare the total cost of the solar system with the total amount of energy that it will produce over its lifetime. This comparison will give you a dollar per unit price that you can compare with the daytime (peak and shoulder) tariffs your electricity retailer offers.

A solar retailer can give you a system’s information for the payment options you are considering, including the `levelised cost of electricity’

Levelised cost of energy (LCOE) - is the average cost of electricity supplied by a solar system over its lifetime, usually in $/kWh, taking into account all finance payments and operating costs. It’s used to compare a finance option with the option of buying electricity from the grid.


Alternative Technology Association (ATA)

Sunulator simulates half hourly solar production and consumption for up to 35 years. It allows you to compare scenarios with different system sizes or orientations or different tariffs. It estimates economic returns for both investors and the site customer.

Solar Payback Calculator


This calculator compares the payback period between two solar systems. It can be used to compare panel quality, orientation, tilt and battery storage options

Solar Power System Payback & ROI Calculator

Solar Choice

The Solar Power System Payback & ROI Calculator allows you to quickly test simple assumptions and system sizes to find the best size for your circumstances.

Solar Power Calculator V2.0


This calculator provides a simple cash flow analysis of solar system options, including finance options for a mortgage or a loan.

Energy Savings Calculator


An energy savings calculator that evaluates finance options and bill savings.

Online Solar Calculator

Green and Gold Solar

A very simple tool that calculates solar production and bill savings.

Solar Savings and ROI Calculator

LG Energy

A simple tool that compares different sizes and works out payback on a chosen option.

Solar Power Savings Calculator


The Solar Power Savings Calculator calculates and compares the annual energy savings and bill savings across a number of system sizes up to 5kW.

Small generation unit STC calculator

Clean Energy Regulator

This small-scale technology certificate (STC) calculator determines the approximate STCs for a solar system

Solar Power Calculator

Solar Calculator

Calculates energy savings for a solar system up to 10kW in size over a 25 year period. It also provides modelling for a 7KWh or 10kWh battery system.

Solar Battery Calculator

Solar Calculator

Calculates savings for households with existing solar systems up to 10kW in size who are looking to install battery storage with up to 10kWh of capacity.

Off Grid Solar Calculator

Solar Calculator

This calculator models the size of the battery and solar system needed to go ‘off-grid’ based on daily electricity use. The calculator also uses a number of variables including the days of storage the battery system would hold, its depth of discharge and any alternative or back-up generation.


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Page last updated: 15 June 2016