Solar Payback Calculators

Solar Mortgage Calculator

Adding the cost of your solar system to your home loan can be a surprisingly affordable option when you take into account your monthly electricity savings.

This calculator shows you how much extra, per month, you would pay (or save) if you installed solar electricity in your home and added the cost of the solar system to your mortgage.

The calculator works out the extra repayments to cover the cost of your solar system but subtracts your monthly electricity bill savings.

A red bar on the graph means that you are paying more that month for solar than you are saving in reduced electricity bills.

A green bar means that your electricity bill savings are greater than your extra repayments and you are saving money compared to life without solar.

You'll see that any extra cost reduces over time. This is because electricity prices will go up, but your repayments will stay the same.

I've made 3 videos that show you how to use the calculators and interpret the results. You can watch them here

Your State:

This determines your Feed In Tariff and estimated power output. (You can override the numbers in Advanced Options)

System Size:

This determines approximate values for the next 2 boxes (cost and electricity output). You can override these with more accurate numbers if you have the information to hand.

Out-of-pocket cost for the quoted solar system.
$

Enter the price you will pay after you have claimed all rebates and RECs.

Upfront Payments (optional)
$

Enter any upfront payment that you would like to make.

Annual Solar System output in kWh

This is the electricity output of the system as estimated in your quotation.

Price per kWh you currently pay for electricity
cents

You can find this on your bill. 19c per kWh is typical.

Show Advanced Options
Annual bill inflation %	Enter approximate annual bill increase (3% is optimistic, 7% is pessimistic)
Feed In Tariff % at cents per kWh	The percentage of electricity generated that you estimate will earn the FIT rate.
Feed In Tariff Duration years	Feed In Tariff Duration
System Degregation % per annum	All systems degrade over time, good ones at less then 0.5%, cheaper ones at closer to 1%
Assume Inverter Replacement $ after years	Generally, good inverters should last about 20 years
Include Opportunity Cost % per annum	This is the cost of money that could have been invested instead

Extra cost/savings per month if you add to your mortgage:

Interest rate
%

Term
years

Over years:		$
	b) Total Electricity Savings:	$
		$
	Payback:

How to read the graph: the bars show the cost/savings over time of owning the quoted solar system. It is your electricity bill savings minus the extra repayments to pay for the system. If the bar is green, then you are saving money that month compared to life without solar! Hover your mouse over a month to see the cost/savings.