Francesco Zinghinì
Author and curator of WaterHeaterCalcs.
Author and curator · WaterHeaterCalcs
Francesco Zinghinì is the author and curator of WaterHeaterCalcs. This is a truthful role: I am not a licensed plumber, a gas fitter or any trade professional, and I do not claim any such credential.
My relevant, verifiable competence is building deterministic online calculators (open-source Python projects) and electronic-engineering training (Systems Theory, Sapienza University of Rome) — which gives genuine rigor on the water-heater sizing, energy and cost arithmetic. Water-heater sizing is first-hour-rating and flow/temperature math (FHR = usable storage + recovery; tankless GPM = Σ fixture flow at ΔT = output − inlet), energy is closed-form thermodynamics (BTU = gallons × 8.33 × ΔT; kWh = BTU ÷ 3412 ÷ UEF; therms = BTU ÷ 100000 ÷ UEF) and cost is a quantity × unit-price sum (cost = parts/unit + labor + add-ons) — verified numerically on known examples. Every formula on this site shows its basis, every convention is cited under Sources, and every calculator is numerically self-checked against known values (see Methodology).
Everything here follows one rule: the tools must stay correct with no ongoing maintenance. That is why every cost tool works only on the routine you measure and the prices you enter from your own quotes and bills, and every energy tool on your own $/kWh and $/therm — the site keeps no utility rate, no equipment or labor price list and no live rates that would silently go stale. The only baked-in numbers are stable physical identities (8.33 lb/gal, 3412 BTU/kWh, 100000 BTU/therm, BTU = gallons × 8.33 × ΔT) and clearly labeled published typicals (DOE hot-water use, gallons + FHR by household, UEF, lifespan, inlet temperature, cost bands) you can adjust to your own unit.
A water heater is a real spend and a real safety device, so every cost tool is framed as a planning estimate, not a bid; every sizing / energy tool reminds you to confirm your unit’s rated First-Hour Rating, GPM and UEF on its EnergyGuide label and round up; and the type / lifespan / UEF references note their values are labeled typicals, not a certified spec — and that gas, venting, combustion, the temperature-&-pressure relief valve and the scald / Legionella tradeoff are a licensed plumber / gas fitter, manufacturer-instruction and local-code matter. The aim is a neutral, free, no-signup reference you can use to sanity-check a plumber’s numbers — nothing that pretends to replace a professional plumber, gas fitter or local code.
Elsewhere
Reach me through the contact page.