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Hot Water Heater Size Formula:
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The hot water heater size calculation determines the appropriate tank size needed to meet hot water demand based on flow rate, temperature rise, and recovery rate. Proper sizing ensures efficient operation and adequate hot water supply.
The calculator uses the hot water heater size formula:
Where:
Explanation: The formula calculates the required tank size by considering the hourly hot water demand, the temperature increase needed, and the heater's ability to recover heat.
Details: Correct hot water heater sizing is crucial for energy efficiency, cost savings, and ensuring adequate hot water supply. Oversized heaters waste energy, while undersized heaters cannot meet demand.
Tips: Enter GPH based on your peak hot water usage, ΔT based on your climate and desired water temperature, and recovery rate from your heater's specifications. All values must be positive numbers.
Q1: What is a typical GPH for residential use?
A: Typical residential GPH ranges from 30-60 gallons per hour depending on household size and usage patterns.
Q2: How do I determine the correct ΔT?
A: ΔT is the difference between your incoming cold water temperature (usually 40-50°F) and desired hot water temperature (typically 120°F).
Q3: What is recovery rate?
A: Recovery rate is the amount of water the heater can heat to the desired temperature in one hour, expressed as a percentage of tank capacity.
Q4: Should I round up the calculated size?
A: Yes, it's generally recommended to round up to the nearest standard tank size to ensure adequate capacity.
Q5: Does this calculation work for tankless water heaters?
A: This formula is primarily for storage tank water heaters. Tankless heaters are sized based on flow rate and temperature rise requirements.