Water heating calculators

Size your hot water before you buy it.

Tank gallons, tankless GPM, recovery, running cost, and payback — enter your numbers and see every step of the math. No account needed.

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Standard breaker rating from the load, checked against the NEC 310.16 ampacity of the conductor and the 240.4(D) small-conductor limits.

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Dwelling service load by the NEC 220.82 optional method, from floor area, circuits, fixed appliances and HVAC.

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Rank appliances by what they cost to run, with duty cycle, standby draw and each one's share of the bill.

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Turn a metered month into a monthly and annual bill, the effective all-in rate, and the water heater's share of it.

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