Water Heater Conversion ROI Calculator

Estimate the payback period for switching between gas and electric water heaters (Singapore market).

Inputs

Electricity Tariff (SGD / kWh, before GST) Gas Tariff (SGD / kWh, before GST) Electricity Annual Increase (%) Gas Annual Increase (%) GST (%)

Household Size (people) Hot Water per Person (litres / day) Cold Water Inlet Temp (°C) Heater Control Type Dial Setting on Heater (°C)

Typical regulator setting: 38–42°C for shower comfort.

Current Electric Tank (litres) — 0 = instant New Gas Tank (litres) — 0 = instant

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Heating energy = litres × ΔT × 0.001163 kWh/(L·°C). Standby loss applies when tank capacity > 0.

Conversion Cost (SGD) Electric Replacement Cost (if NOT switching) Cashback / Rebate (SGD) Active Usage Months / Year

Payback Period

— yrs

Break-even at month —

Net Investment

—

Year-1 Annual Savings

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10-Year Cumulative Savings

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Year	Annual Savings	Cumulative Savings	Net Position

Net Position = Cumulative Savings − Net Investment. The highlighted row contains the break-even month.