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Power bill reduction  

How much should my electricity bill go down with solar?

We are going to call kWh units (as Synergy do on their bill) for simplicity.

Let's start with the solar installation. Let's say you have a 6kW system making 25 units of power per day on average across the year.

Now let's say that your home uses 10 units of power in daylight hours (what you use after the solar has shut down is irrelevant).


10 units of solar power used @ $0.2647 inc GST each = $2.647 per day
15 units of solar power exported @ $0.0714 = $1.07 per day
Total daily saving = $3.72
Annual saving = $1357


The table on this web page allows you to add any combination of panels on any roof orientation and see what the power consumption would be, and also what your power bill savings would be, based on whether your day time power use was 5,10,15,20 or 25 units per day.

You already have solar and don't think it's reducing your bill?

The most frustrating thing about Synergy bills is that they don't show how many units of solar power were used in your home during the day, the bill only shows on the back page, how many units of power were exported back into the grid. It's very annoying, but, due to the way our meters work in WA (net metering), unavoidable.

However, the solution is relatively simple.

If you know your typical billing day cycles from Synergy, then you can take a 'total production reading from your solar inverter once every two months at the start of the billing period (or refer to your software if you have WIFI reporting).

e.g. let's say your billing cycle is Jan 21st to March 21st, March 22nd to May 23rd etc

You take a reading on Jan 21st from your solar inverter, let's say it's 9056. You take another reading on March 21st and let's say it's 11105. Deduct one from the other and your solar produced 2049 units. Wait for your Synergy bill to come in, and flick over to the REBS section where it shows how many units were exported back into the grid. Let's say it says 490.

So now you have everything you need.

Solar produced 2,049 units

490 units were sold back into the grid at 7.14 cents = $34.99

Leaving 1,159 units used by your house saving 26.47 cents each = $306.79

Total saving $341.78

If recording your solar is a bit too hard to do reguarly, then a much easier way to figure out reasonably accurately what the solar should have produced is to use the calcuator here.



 is the web site for Good Day Mate Pty Ltd trading as SOLAR4EVER Company registered in WA on 26th October 2008 (A.C.N.133884938)

Contact Detail :

Telephone : (08) 6102 2527