Got solar, but your power bill is still high?
Solar cuts your bill by the power you use while the sun is up. It does far less for the power you use at night, and almost nothing for the power you send back to the grid. Most high bills after solar come down to one of these six things.
The short answer
- Most common reason: you use most of your power in the evening, when the panels aren't producing.
- Second: exported solar earns very little. Buying a kWh costs many times what exporting one earns.
- Check too: your plan, your system's output, and new big appliances.
1. You use most of your power after dark
Panels only help while the sun is up. If the house is empty all day and busy from 5pm, you buy most of your power from the grid at full price.
Fix: move what you can into the day, using timers on the dishwasher, washing machine, pool pump and hot water. A battery stores the midday surplus for the evening.
2. Exporting earns almost nothing
The rates our calculator uses for buying and exporting power show the gap[1]:
- Victoria: about 30c a kWh to buy, about 1c to export.
- NSW: about 30c to buy, 3.4c to export.
- Queensland: about 28c to buy, 2.5c to export.
- South Australia: about 42c to buy, 1c to export.
Every kWh you use yourself is worth far more than one you export. A system sized for a big export credit does not pay the way it used to.
3. You're on the wrong plan
Retailers change rates and feed-in tariffs, and plans that suited you at install may not now. A time-of-use plan can cost more if your heavy use falls in the evening peak. Compare your plan against your smart meter data on the government's comparison site: Energy Made Easy, or Victorian Energy Compare in Victoria.
4. The system isn't producing what it should
- Check the inverter app or screen. A fault light, or days of zero output, means a problem.
- Dirty panels, new shade from trees or a neighbour's extension, or a failed inverter all cut output quietly.
- Compare this month's output to the same month last year.
5. Your usage has grown
A new air conditioner, a pool, more people at home, or an electric car can outgrow a system sized years ago. Your bill shows your daily use: compare it to the year you installed.
6. Winter
Shorter days and a low sun mean far less solar, just when heating runs. A winter bill being higher is normal. Compare winter to winter, not winter to summer.
Why two quotes for the same job can be thousands apart
Installers price the same system very differently. These are the installed price ranges our calculator works from, before rebates: the low end is what a competitive installer charges, and the high end is what a poor quote looks like.
| System | Competitive quote | Poor quote |
|---|---|---|
| 6.6kW solar system | $8,000 | $10,000 |
| 10kWh battery | $7,650 | $13,500 |
| About 15kWh battery | $12,100 | $18,000 |
- The gap usually comes from margin, the brand of panel, inverter or battery, and extras such as a switchboard upgrade or backup circuit, not from a better install.
- Get at least two or three quotes, and ask for each to be itemised: hardware brands and models, size, rebates taken off, and anything extra.
- Compare batteries on price per usable kWh, not the headline price.
Get the numbers for your own home
Two minutes of questions about your bill, roof and routine gives you the system size, what it should cost after rebates and what it saves. Your report shows on screen straight away, and no installer sees anything unless you ask.
Run my numbers, freeCommon questions
Why is my bill so high when I have solar?
Usually because most of your use is in the evening, when panels aren't producing, and because exported power earns very little compared with what buying it costs.
Will a battery lower my bill?
If you use a lot of power in the evening and export a lot during the day, usually yes. It stores your midday surplus for the evening.
How do I know if my solar is working?
Check the inverter app or display for faults and daily output, and compare it with the same month last year.
Should I add more panels?
Only if you can use the extra power in the daytime, or store it. Extra exports earn little.
Sources
- Aussie Solar Info, How the calculator works: the electricity and feed-in rates it uses for each state, checked August 2026. Read 4 November 2026.