15 L vs 25 L geyser

Star labels measure standing heat loss while the tank is on. Heating water for a bath uses roughly litres × ΔT × 0.001163 / efficiency — independent of star rating.

Worked example

Four people, two showers/day, 18°C inlet and 40°C target: about 60 L hot water/day → ≈ 1.71 kWh/day heating at 90% efficiency assumption.

Retail advice splits 15 L vs 25 L for 3–4 users; we show a range because usage and inlet temperature matter.

Open the Geyser Picker with your tariff and schedule.

Last reviewed: 2026-11-05 · Editorial