Hot Water Heating Cost Calculator
Calculate daily and annual thermal energy and fuel cost from your water volume, density, specific heat, temperature rise, efficiency, and tariff.
Heat/day = L/day × kg/L × kJ/(kg·°C) × °C ÷ 3,600; purchased energy = heat ÷ efficiency fraction. Cost = energy × entered price; annual values use 365 days. No physical constants are prefilled. Storage and pipe losses are excluded; this is not temperature-safety guidance. L ≥ 0; ρ > 0; c > 0; ΔT ≥ 0; 0 < η ≤ 100%; r ≥ 0
A QUICK WALKTHROUGH
How to use this tool
- Calculate daily and annual thermal energy and fuel cost from your water volume, density, specific heat, temperature rise, efficiency, and tariff.
- Heat/day = L/day × kg/L × kJ/(kg·°C) × °C ÷ 3,600; purchased energy = heat ÷ efficiency fraction. Cost = energy × entered price; annual values use 365 days. No physical constants are prefilled. Storage and pipe losses are excluded; this is not temperature-safety guidance.
Formula and scope
Heat/day = L/day × kg/L × kJ/(kg·°C) × °C ÷ 3,600; purchased energy = heat ÷ efficiency fraction. Cost = energy × entered price; annual values use 365 days. No physical constants are prefilled. Storage and pipe losses are excluded; this is not temperature-safety guidance. L ≥ 0; ρ > 0; c > 0; ΔT ≥ 0; 0 < η ≤ 100%; r ≥ 0
Assumptions
All numerical inputs are user supplied; no numerical recommendations are prefilled.
Local processing
Values stay in your browser.
GOOD TO KNOW
Common questions
What does this estimate?
It calculates only from your inputs; it is not equipment or safety advice.
Are inputs uploaded?
No. All calculations run locally in your browser.