Home
Back
BTU/hr Formula:
| From: | To: |
The BTU Water Heater Calculator determines the required heating capacity in BTU per hour for water heating applications. It helps in sizing water heaters for residential, commercial, and industrial use based on flow rate, temperature rise, and system efficiency.
The calculator uses the BTU/hr formula:
Where:
Explanation: The formula calculates the energy required to heat water by accounting for flow rate, temperature rise, and accounting for system efficiency losses.
Details: Accurate BTU calculation is essential for proper water heater sizing, ensuring adequate hot water supply while optimizing energy efficiency and preventing equipment oversizing or undersizing.
Tips: Enter flow rate in GPM, temperature difference in °F, and system efficiency as a decimal (e.g., 0.85 for 85% efficiency). All values must be positive numbers.
Q1: What is a typical efficiency value for water heaters?
A: Standard tank water heaters typically have 80-85% efficiency, while tankless models can reach 90-95% efficiency.
Q2: How do I determine the temperature difference (ΔT)?
A: ΔT is the difference between desired hot water temperature and incoming cold water temperature. Typical values range from 40°F to 90°F depending on application.
Q3: What flow rate (GPM) should I use?
A: Calculate based on simultaneous fixture usage. Standard fixtures: shower (2.5 GPM), sink (1.5 GPM), bathtub (4.0 GPM).
Q4: Why is 8.34 used in the formula?
A: 8.34 represents the weight of one gallon of water in pounds, which is used to convert volume flow to mass flow for energy calculations.
Q5: Can this calculator be used for commercial applications?
A: Yes, this calculator works for both residential and commercial water heating systems, though commercial applications may require additional factors.