Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Plumbing
Hot Water Recirculation Calculator
Estimate the heat loss in a hot water recirculation system based on pipe length, diameter, insulation quality, and acceptable temperature drop. Use this when designing or auditing a recirculation loop to minimize wait time and energy waste.
Fill in the required fields to see your result.
Plumbing
Water Heater Sizing Calculator
Determines the minimum tank capacity (in gallons) your household needs based on occupants, bedrooms, bathrooms, usage pattern, and heater efficiency. Use it before buying or replacing a water heater.
Fill in the required fields to see your result.
Key differences
| Hot Water Recirculation Calculator | Water Heater Sizing Calculator | |
|---|---|---|
| Category | Plumbing | Plumbing |
| Inputs required | 4 | 5 |
| Result | Required Flow Rate (GPM) | Recommended Tank Size (gallons) |
| What it does | Estimate the heat loss in a hot water recirculation system based on pipe length, diameter, insulation quality, and acceptable temperature drop. Use this when designing or auditing a recirculation loop to minimize wait time and energy waste. | Determines the minimum tank capacity (in gallons) your household needs based on occupants, bedrooms, bathrooms, usage pattern, and heater efficiency. Use it before buying or replacing a water heater. |