Most batteries installed under the Cheaper Home Batteries Program are retrofits: the owner already has solar and adds storage later. That is exactly what the program was designed for, and it does not matter how old the solar is.
What the battery must meet
- CEC-approved battery, with the right to be VPP-capable.
- Installed by an accredited installer.
- Between 5 and 100 kWh usable capacity, with up to 50 kWh eligible for certificates.
- One battery per property.
- Installed on or after 1 July 2025. A battery installed before that date is not eligible.
Batteries are claimed with evidence rules that tightened from 1 March 2026; see the battery submission guide and the program installer guide.
How the STC number is worked out
The number of certificates is the usable kWh, run through the tiers, multiplied by the factor. Since 1 May 2026 the first 14 kWh counts at 100 per cent of the factor, 14 to 28 kWh at 60 per cent and 28 to 50 kWh at 15 per cent. The factor is 6.8 at the time of writing, stepping down to 5.7 on 1 January 2027 and 5.2 on 1 July 2027.
A 13.5 kWh retrofit battery today earns about 13.5 x 6.8 = 91 STCs, and at the roughly $38 to $40 spot range at the time of writing that is about $3,500 to $3,600 in certificate value. The same battery on 1 January 2027 would earn about 13.5 x 5.7 = 76. A 20 kWh battery would earn 14 x 6.8 plus 6 x 6.8 x 0.6, about 119. Use the battery STC calculator for any size and date.
Existing solar, any age
Because the program does not require new solar, a 10-year-old system can pair with a retrofit battery. The practical question is the inverter: a retrofit may need a hybrid inverter, a battery inverter or an AC-coupled battery, and the installer should confirm compatibility. Replacing the inverter does not earn solar STCs; see replacing an inverter.
One per property
The limit is one battery per property. If the owner already has an eligible battery, a second one is not eligible. Expanding an existing battery is covered on its own page: expand an existing battery.
What this means for installers
Confirm the date of installation, because the factor changes on 1 January 2027, and capture photos to the March 2026 evidence standard. Quote the STC discount from the current factor and tiers. The battery STCs page covers payment, and current rates are published.
For the process end to end, see STC trading.