What size system do we actually need for our house and winters here?

100UP uses a straightforward sizing rule: 5 kWh for the house, plus 5 kWh per person based on bedroom capacity — the 100UP Way.

That ties system size to occupancy and winter performance, not annual averages or nameplate ratings alone. Examples:

• 1-bedroom property: 10 kWh/day baseline
• 2-bedroom property: 20 kWh/day baseline
• 4-bedroom property: 30+ kWh/day for full family occupancy

We then model worst-case winter for your location — June/July cloud, short daylight — not best-case summer production.

Winter sizing is the engineering call that decides whether the system works through a Ballarat July or merely looks good on paper.