Your bill may stay high because you use a lot of electricity when solar is not producing, your system may be too small for your current needs, your usage may have increased, or the existing system may not be performing as expected. The bill and system details usually tell us where to look first.
Solar only helps when it is producing
If most of your electricity is used in the evening or overnight, you can still buy a lot of power from the grid even though your panels produced useful energy during the day.
Your energy use may have changed
Many homes use more electricity than they did when the solar system was first installed. EV charging, air conditioning, pools, electric hot water, working from home and replacing gas appliances can all increase demand.
The system may be too small now
A system that suited the household several years ago may not suit it today. Before jumping to a battery, I check whether daytime grid imports show that more solar should be considered first.
You may export cheaply and buy back later
A home can export solar during the middle of the day and then buy electricity from the grid later. A battery may help in some cases, but only if there is enough surplus energy to store and enough later use to make that stored energy valuable.
The tariff can matter
Electricity rates, time-of-use periods, controlled loads and feed-in tariffs can all change the result. Sometimes the system is working normally but the tariff is not a good fit for the way the household now uses energy.
Check performance before spending more
If bills rise unexpectedly, I also want to know whether the inverter is operating normally and whether recent generation is consistent with what the system should reasonably produce.
A simple example
A household has 6.6 kW of solar but has added an EV and now uses much more electricity after 5pm. The solar system may still be working properly. The higher bill may simply reflect new energy use occurring after solar production falls.
What I look at
- Recent bills and seasonal usage
- Existing solar size and age
- Solar exports
- Daytime versus evening grid purchases
- Inverter details and system performance
- New loads such as EVs, pools or electric heating
- Current tariff and feed-in tariff
The next step might be more solar, a battery, a system upgrade, a tariff review, or no change at all. The right answer depends on what the existing system is actually doing.
Want to understand your existing system?
Start with your electricity bill and the details of the solar system you already have.