Right size geyser or water heater in litres and gallons for your family and showers.
How this works
Hot water per shower = minutes x flow x 60% hot. Add about 5 L per person for basins and kitchen. A storage heater should hold about 70% of the daily need (the morning peak). Heat needed = litres x temperature rise x 1.163 Wh.
Questions people ask
How do I use the Water Heater Geyser Size tool?
Fill in the fields, starting with “People”, “Showers per person per day” and “Shower length”, and change any other options that match your home. The answer, a drawing and practical tips update as you type, and the Copy link button saves your numbers in a link you can share.
Is the Water Heater Geyser Size tool free?
Yes. The Water Heater Geyser Size tool is free, with no sign-up, and works on phones, tablets and computers. The results are estimates to help you plan, so check with a qualified professional before structural, electrical, gas or plumbing work.