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Electric Tankless Water Heater Formula:
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The Electric Tankless Water Heater Calculator determines the required power (in kilowatts) for an electric tankless water heater based on flow rate and desired temperature rise. This helps ensure proper sizing for efficient and effective hot water delivery.
The calculator uses the tankless water heater formula:
Where:
Explanation: The formula calculates the energy needed to heat water based on flow rate and the temperature difference between incoming cold water and desired hot water output.
Details: Correctly sizing an electric tankless water heater is crucial for ensuring adequate hot water supply, energy efficiency, and preventing system overload. Undersized units cannot meet demand, while oversized units waste energy and money.
Tips: Enter flow rate in gallons per minute and desired temperature rise in degrees Fahrenheit. Typical flow rates: shower (2-2.5 GPM), kitchen faucet (1.5-2 GPM), bathroom faucet (0.5-1.5 GPM). Temperature rise depends on incoming water temperature and desired output temperature.
Q1: What is a typical temperature rise for tankless water heaters?
A: Typical temperature rise ranges from 40°F to 70°F, depending on climate and incoming water temperature. In colder climates, higher temperature rises may be needed.
Q2: How do I determine my required flow rate?
A: Calculate the total flow rate by adding up the GPM of all fixtures that might run simultaneously. For example: shower (2.5 GPM) + kitchen faucet (2 GPM) = 4.5 GPM total.
Q3: What factors affect the calculation accuracy?
A: Incoming water temperature, simultaneous fixture usage, and specific fixture flow rates can affect accuracy. Always add a safety margin of 10-20% to your calculated power requirement.
Q4: Can I use this calculator for gas tankless water heaters?
A: No, this calculator is specifically for electric tankless water heaters. Gas units use BTUs and have different sizing calculations.
Q5: What electrical requirements should I consider?
A: Higher kW units require higher amperage circuits. Consult an electrician to ensure your electrical panel can handle the load and proper wiring is installed.