Scenario guide: 3-bed family in Perth

This is an illustrative scenario based on typical Perth household data and Synergy tariff structures, not a specific customer story. Your results will depend on your actual usage, tariff and system configuration.

Home profile

• Occupants: 3 (2 adults, 1 child)
• Cooling/heating: Reverse-cycle split system
• Hot water: Electric storage on timer (runs at 11 am)
• Daily usage: ~18-22 kWh, with evenings as the peak demand period
• Grid connection: Single-phase, Synergy A1 flat tariff

System

• Solar: 6.6 kW PV (north-facing roof)
• Battery: 10 kWh usable capacity
• Backup: Essential-circuits only (lights, fridge, comms, one power circuit)
• Goal: Cut evening grid imports and maintain basic function during outages

How this typically plays out

Summer (Oct-Mar): Solar generation peaks at 30-35 kWh/day. The battery charges fully by midday and provides 5-7 hours of evening coverage. Most households with this profile export 8-12 kWh daily, earning DEBS credits.

Shoulder months (Apr-May, Sep): Solar drops to 20-25 kWh/day. The battery still charges fully on clear days. Evening coverage typically stretches to 10-11 pm.

Winter (Jun-Aug): Solar generation drops to 15-20 kWh/day. The battery may not fully charge on cloudy days. Enabling a small forced-charge window on off-peak periods can restore full evening coverage. See our winter strategy guide.

Key takeaways

• Battery size matched to night load is the main driver of value. This household uses ~8-10 kWh between 6 pm and 6 am, so 10 kWh provides strong coverage.
• A simple backup circuits map prevents overloads during outages. The 10 kWh battery can run essential circuits for 8-12 hours depending on load.
• Time-of-use tariffs + automation can improve winter outcomes by charging the battery during off-peak grid periods.
• The DEBS export rate (currently ~2c/kWh off-peak) means self-consumption of solar via the battery is far more valuable than exporting.

Where next

How to size a battery for your usage

A step-by-step method covering evening usage and seasonal AC demand.

Where to place a battery in a Perth home

AS/NZS 5139 clearance rules, garage vs outdoor walls, and what installers check on-site.

WA battery rebate: are you eligible?

Synergy customers get $130/kWh back, capped at $1,300.

Explore your options

Answer a few questions and see systems and installers that fit your home.