Water Heater Cost Calculator
Fill in the values and the answer updates as you type.
How the Water Heater Cost Calculator works
Heat needed (kWh) = litres × 4.186 kJ/kg·°C × temperature rise ÷ 3600, divided by heater efficiency. Electric resistance heaters are close to 95–100% efficient, heat pumps can exceed 300%. Standby tank losses are not included. Example: with the default values, energy per day comes to 7.3 kWh.
Inputs and results
The Water Heater Cost Calculator takes 5 inputs and gives 3 results.
What you enter
- Hot water used per day (L) — starts at 150.
- Incoming water temperature (°C) — starts at 15.
- Heated temperature (°C) — starts at 55.
- Heater efficiency (%) — starts at 95.
- Energy price ($/kWh) — starts at 0.15.
What you get
- Energy per day (kWh)
- Monthly cost
- Yearly cost
Example: Water Heater Cost Calculator with the starting values
With hot water used per day 150 L, incoming water temperature 15 °C, heated temperature 55 °C, heater efficiency 95 % and energy price 0.15 $/kWh, the calculator returns:
| Energy per day (kWh) | 7.3 |
|---|---|
| Monthly cost | $33.05 |
| Yearly cost | $402.08 |
Change any value above and the results update straight away.
Water Heater Cost Calculator FAQ
How do I use the Water Heater Cost Calculator?
Enter hot water used per day, incoming water temperature, heated temperature and heater efficiency in the fields, then read energy per day (kwh), monthly cost and yearly cost in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Water Heater Cost Calculator calculate?
Energy and cost to heat your daily hot water. It returns energy per day (kwh), monthly cost and yearly cost from the 5 values you provide.
What values does the Water Heater Cost Calculator start with?
It opens with hot water used per day 150 L, incoming water temperature 15 °C, heated temperature 55 °C and heater efficiency 95 % so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Water Heater Cost Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Water Heater Cost Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.