Water Heater Size Calculator

It takes Number of people and derives Recommended capacity from them. The calculation is live as you type, so the result updates on every change.

A single value: Number of people. Nothing else is required — no account, no file upload.

With Number of people = 3, the calculator returns Recommended capacity = 150 L. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

It moves a lot. Using Number of people = 6 instead, Recommended capacity goes from 150 L to 300 L — which is why it is worth testing a few scenarios rather than trusting a single figure.

Scaled down to Number of people = 2, Recommended capacity comes out at 100 L. The relationship is worth checking at both ends before you rely on a single result.

Putting a number on a bill: what an appliance costs to run, whether a solar array covers the load, and how much heating a room actually needs.

Confusing power with energy. A kilowatt is a rate and a kilowatt-hour is a quantity; a 2 kW heater on for half an hour uses 1 kWh, and only the second figure appears on a bill.

This one returns Recommended capacity; the Solar battery size calculator returns Battery capacity (kWh). That is the whole difference — open the one whose figure you need.

Generator size calculator is the closest one after this: Estimate the generator size you need from the wattages of your appliances.

TV Size Calculator and Battery life calculator — they come up in the same task often enough to be worth a second tab.