Operating Cost & Energy
The operating-cost & energy cluster — pure thermodynamics + your utility rate: a water-heater operating-cost calculator (annual BTU ÷ 3412 ÷ UEF × your $/kWh, or ÷ 100000 ÷ UEF × your $/therm), a tankless-vs-tank payback, heat-pump / hybrid savings, cost per shower, and energy cost by fuel. Enter YOUR $/kWh and $/therm — these are typical planning values; confirm your unit's UEF on its EnergyGuide label.
Typical planning values. Your real hot-water use, incoming water temperature, recovery and efficiency vary by household, unit, fuel and region — confirm your unit’s rated First-Hour Rating, GPM and UEF on its EnergyGuide label and the manufacturer’s instructions. Round sizing up, and leave headroom for peak demand.
Operating-Cost CalculatorEstimate what a water heater costs to run each year from first-principles thermodynamics and the utility rate you enter — electric kWh or gas therms, by UEF.Tankless-vs-Tank PaybackCompare the yearly running cost of a tank and a tankless water heater and find the payback on the upfront premium, using your gas rate, UEFs and price gap.Heat-Pump SavingsSee how much a heat-pump (hybrid) water heater saves each year versus an electric resistance tank — same delivered heat, your kWh rate and both UEF values.Cost per ShowerWork out what one hot shower costs in electricity from the gallons used, your temperature rise, the unit's UEF and your kWh rate — the bill's real driver.Energy Cost by FuelCompare the annual cost of heating the same water with electricity, natural gas and propane, priced on identical delivered BTU using your rates and UEFs.
Every Operating Cost & Energy 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.