Planning & Reference
The planning / reference cluster: lifespan by type, a maintenance & flush schedule, the 120 °F temperature-setting reference (the scald vs Legionella tradeoff, deferred to the manufacturer and a pro), how to size a water heater (the deterministic peak-demand → FHR method), and an anode-rod & tank-protection reference. Labeled planning typicals, not a certified spec.
Typical published planning values — NOT a certified spec or professional advice. Efficiency, sizing and life vary by unit and installation; confirm on the EnergyGuide label and the manufacturer’s instructions. Water-heater installation, gas, venting, combustion, the temperature-&-pressure relief valve, and the scald / Legionella tradeoff of a temperature setting are a licensed plumber / gas fitter, manufacturer-instruction and local-code matter — not engineered here.
Lifespan by Type ReferenceTypical water heater lifespan by type: gas tanks last about 8–12 years, electric 10–15, tankless 18–20. See what drives the range and when to replace it.Maintenance & Flush ScheduleWater heater maintenance schedule: flush the tank yearly, check the anode every 2–3 years, test the T&P valve yearly, and descale a tankless in hard water.Temperature-Setting Reference (120 °F)What temperature should a water heater be? 120 °F is the common recommendation – the scald vs bacteria tradeoff and the effect on your running cost, explained.How to Size a Water HeaterHow to size a water heater: add up the busiest hour of hot-water use, then pick a tank First-Hour Rating above it or a tankless GPM at your temperature rise.Anode-Rod & Tank-Protection ReferenceAnode rod reference: magnesium for soft water, aluminum for hard water, powered for no maintenance or a rotten-egg smell – check every 2–3 years.
Every Planning & Reference tool is calculated server-side — visible immediately — with its formula, a worked example and a reference table, and works on the routine you measure and the prices you enter from your own quotes. Background reading is in the guides.