The system and its numbers
The house: a roof, a garage and no gas.
Written 26 Oct 2026Last checked 26 Oct 2026Applies to the house as at 26 Oct 2026; meter figures to 25 Oct 2026Stage Working
My house is a 1990s brick-veneer in Melbourne's south-east. I moved heating and hot water off gas in August 2025, the gas meter came out in November, and the solar and battery went live on 28 November. Since then everything runs on electricity from the roof, the battery in the garage and the grid, with Home Assistant deciding when to charge, hold and export.
What's installed
| Solar | 19.38 kWp | 38 Jinko 510 W panels in four strings, one facing west, one north and two east. |
|---|---|---|
| Controller | 20 kW, three-phase | SigenStor EC 20.0 TP AU, the inverter and battery controller in one box in the garage. |
| Battery | 48.36 kWh | six SigenStor BAT 8.0 modules, about 46.8 kWh usable, stacked in the garage. |
| Export limit | 15 kW | set for this connection, 5 kW on each phase. |
| Heating and hot water | All electric | reverse-cycle air conditioning and a heat-pump hot-water system. The gas meter is gone. |
| Meter and control | AusNet smart meter, read every half-hour, and Home Assistant talking to the controller over Modbus. |
A day in the life
The house at Tue 27 Oct 2026 09:49 AEDT
Read from Home Assistant when this page was last built. Power is the reading at that moment; energy is the total from midnight to then.
Saturday 24 October 2026
The year in numbers
The 332 days since the solar and battery went on.
Most of what I buy is free: from June the battery has been filled from the grid in each plan's free midday window.
The cliff, and what it cost
Every half-hour since July 2024
The retailers
Red Energy, Time of Use
- Peak
- 3 to 9 pm, 40 c
- Off-peak
- 23 c
- Cost
- 31 c a kWh bought
Electricity and gas on one account while the house still had gas.
Amber Electric
- Plan
- Wholesale prices, passed through half-hourly
- Cost
- 28 c a kWh bought
I wanted to run the battery against wholesale prices and see them directly. What the bills showed.
OVO Energy, The Basic Free 3
- Free
- 11 am to 2 pm
- Peak
- 3 to 9 pm, 40 c
- Feed-in
- 1 c
- Cost
- 7 c a kWh bought
Three free hours at midday fill the battery for winter evenings.
GloBird, ZEROHERO
- Free
- noon to 3 pm, up to 50 kWh a day
- Export
- 10 c for the first 15 kWh, 6 to 9 pm
- Credit
- $1 a day if evening import stays under 0.03 kWh an hour
It pays for an evening export that a 15 kW limit and 48 kWh of battery can supply.
The reasoning for each switch: The switching question.
What changed, and what's next
- Gas, 2006 to 2025. I put gas into the house in 2006 – it made financial sense then. Heating and hot water went electric in August 2025, and the gas meter was abolished in November.
- All-electric, August 2025. Daily import rose from 17.4 to 27.6 kWh once heating and hot water ran on electricity.
- Solar and battery on, 28 November 2025. Import fell to 15.0 kWh a day on average, most of it free midday charging, and 4,151 kWh has gone back to the grid.
- Next: the cooker. It sits on the grid side, so evening cooking still buys at 44 c. Moving it onto the battery-backed side is the next job, and GloBird's first bill will replace the modelled figure above.