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Power bill reduction  

How much should my electricity bill go down with solar?

How much your power bill reduces is a fairly simple bit of maths.

Any units (kWh) of solar power used in your house are worth whatever you pay for a unit of electricity. Typically in the 26c to 35c range depending on where you are.

Every unit of power that is exported to the grid as surplus to your immeadiate needs is worth whatever your electricity retailer is prepared to pay you for it. Typically 7 cents to 16 cents.

So, in simple terms if you pay 30 cents for power and get paid 15 cents for surplus, then if your solar has made 30 units for the day and the home has used up twenty of them then your saving is...

20 x 30 cents + 10 x 15 cents = $7.50 for the day

If exactly the same happened every day then your annual saving would be $2737.50

If you already have the right sort of digital meter you can, before you buy solar, see what your power use is minute by minute, hour by hour and get a good idea of how much power you are likely to use up from your solar. The rest will be exported unless you buy a battery.

How much power the solar makes is dependent on where you live but as a very rough rule of thumb work on 4.5 units of power per kW of solar panels per day on a North roof and 4 units of power for an East or West roof.