Before you get a single solar quote, spend five minutes with your electricity bill. It contains the most important data for sizing a solar system correctly — and knowing how to read it puts you in a much stronger position when you're talking to installers.
The Numbers That Matter for Solar
Daily Average Usage (kWh/day)
This is the most important number. It's usually shown prominently on Australian bills as "average daily usage" in kWh. If it's not shown directly, divide your total consumption for the billing period by the number of days in the period.
The typical Australian household uses 15–25 kWh/day. Yours will vary based on household size, whether you have electric hot water or gas, whether you have a pool, and your climate zone.
Total Consumption (kWh)
Your total electricity usage for the billing period. Bills are usually quarterly (90 days) or monthly. If quarterly, divide by 90 for your daily average.
Your Electricity Rate (c/kWh)
Look for "supply charge" or "usage charge" — the rate you pay per kWh imported from the grid. This is the rate your solar self-consumption displaces. In most Australian states in 2026, this is 28–45c/kWh depending on your retailer and tariff structure. This is the number that determines how much each solar kWh is worth to you.
Daily Supply Charge
A flat daily charge (around $0.80–$1.50/day) that you pay regardless of how much electricity you use. Solar doesn't reduce this — it's a fixed cost of being connected to the grid.
Feed-In Tariff / Solar Credits (if you already have solar)
If you already have solar, your bill will show how many kWh you exported and what you were paid per kWh. The exported kWh line tells you your current self-consumption rate — if you exported 60% of what you generated, you're only directly using 40%, which means there's significant room to improve self-consumption through load scheduling or a battery.
Flat Rate vs Time-of-Use: Which Do You Have?
Check whether your bill shows a single usage rate or multiple rates by time period. If you see "peak", "shoulder", and "off-peak" rates, you're on time-of-use pricing. If there's just one usage rate, you're on a flat rate. This affects how you should think about solar sizing and whether a battery makes sense.
What Your Bill Tells an Installer
A good installer will look at: your daily average consumption, your seasonal variation (summer vs winter bills), your tariff structure, and — if you have solar — your export volumes. This information drives every sizing decision they make.
If an installer gives you a quote without seeing your bill, they're guessing. The best installers ask for 12 months of bills. Even one recent bill gives them enough to work with.
The Fast Way: Let GridBeater Do the Reading
Upload your electricity bill to GridBeater and our system automatically extracts your usage data, calculates your savings potential, and gives you an analysis based on your real numbers — not industry averages. It takes 60 seconds and gives you an independent estimate before you've spoken to a single installer.
Upload your bill and see your solar savings estimate → Free at GridBeater