Estimate your busiest hour

Count the uses that overlap

Choose a realistic busy hour, rather than adding every use across the day. Change the sample amounts to match your fixtures and appliance information. A shower’s total flow includes cold water, so it is not automatically its hot-water demand.

How to use the result

For a storage heater, discuss first-hour delivery with your installer. Tank capacity alone does not describe how much heated water a unit can deliver during that hour. This estimate is a conversation starter, not a purchase recommendation.