Choosing a Water Heater (Storage Boiler vs Tankless): Power and Consumption Calculation — Los Angeles

Choosing the right water heater is a balance between comfort, installation limits, and monthly energy costs. In Los Angeles, where many homes have limited space and varied utility setups, the first decision is usually between a storage (boiler/tank) unit and a tankless (instant) heater. Start with demand: list the fixtures that may run at the same time (shower, kitchen sink, dishwasher). For a storage heater, size is measured in gallons and recovery rate. A practical approach is to estimate peak hot-water use: one shower typically needs about 1.5–2.5 GPM of mixed water. If you want continuous showers for a family, a larger tank with a strong recovery rate is often more forgiving than a small tank. For tankless units, the key value is required heating power. Calculate it using flow and temperature rise: Power (kW) ≈ 0.073 × Flow (L/min) × ΔT (°C). Example: 8 L/min with a 25°C rise needs about 14.6 kW. If you want two fixtures simultaneously, add the flows. Then confirm your electrical panel or gas line can support it—electric tankless models may require multiple breakers, while gas units need proper venting and combustion air. To estimate consumption, consider how long you use hot water daily. Energy roughly equals the heat needed to raise incoming water to set temperature, plus losses. Storage heaters have standby losses but lower peak power; tankless heaters minimize standby losses but demand higher instantaneous input. For businesses listed in a Business Directory under Plumbing & Water Systems, these calculations help match the right equipment to your property and avoid undersized, inefficient installations.