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Water Heater Capacity Formula:
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Water heater capacity refers to the amount of hot water a heater can store and deliver to meet household demands. Proper sizing ensures adequate hot water supply while optimizing energy efficiency and equipment lifespan.
The calculator uses the water heater capacity formula:
Where:
Explanation: This formula calculates the minimum tank capacity needed to meet daily hot water demands while accounting for the heater's recovery rate and providing a safety margin for peak usage periods.
Details: Correct water heater sizing prevents energy waste from oversized units and ensures adequate hot water supply from undersized units. Proper sizing extends equipment life and reduces operating costs.
Tips: Enter daily hot water use in gallons, recovery rate in gallons per hour, and select appropriate safety factor. All values must be positive numbers for accurate calculation.
Q1: What is recovery rate?
A: Recovery rate is the amount of water (in gallons) a heater can heat from cold to set temperature in one hour.
Q2: How do I estimate daily hot water use?
A: Calculate based on household size and usage patterns. Average person uses 20-30 gallons of hot water daily for bathing, cleaning, and cooking.
Q3: When should I use safety factor 1.25 vs 1.5?
A: Use 1.25 for standard households, 1.5 for homes with high simultaneous usage (multiple bathrooms, large families).
Q4: Does this work for tankless water heaters?
A: This calculator is primarily for storage tank heaters. Tankless units are sized based on flow rate requirements rather than capacity.
Q5: What are typical recovery rates?
A: Electric heaters: 10-20 gal/h, Gas heaters: 30-50 gal/h, depending on unit size and energy input.