Hot Water Demand Calculator
The Hot Water Demand Calculator finds daily hot-water demand, peak-hour load, and storage tank size for a building. Example: for 50 office workers plus 100 restaurant meals per day, Daily demand = 1650 L/day, Storage tank = 750 L, Heat energy = 61.3 kWh (per ASHRAE HVAC Applications Handbook Ch.50).
How it works
Computed from your inputs per ASHRAE HVAC Applications Handbook Ch.50.
Worked example (Plumbing & Pumps)
Inputs: 50 office workers plus 100 restaurant meals per day.
| Result | Value |
|---|---|
| Daily demand | 1650 L/day |
| Storage tank | 750 L |
| Heat energy | 61.3 kWh |
Computed live by WorkHive's calculation engine; standard: ASHRAE HVAC Applications Handbook Ch.50.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses 50 office workers plus 100 restaurant meals per day.
- The calculator returns Daily demand, Storage tank, Heat energy, computed per ASHRAE HVAC Applications Handbook Ch.50.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a hot water demand and storage calculator?
The Hot Water Demand Calculator is a free online tool that computes finds daily hot-water demand, peak-hour load, and storage tank size for a building. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following ASHRAE HVAC Applications Handbook Ch.50. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Hot Water Demand Calculator in WorkHive: free, no sign-up needed for the calculators.