1. What is a Tankless Water Heater Electric GPM Calculator?

Definition: This calculator estimates the total flow rate (Gallons Per Minute) needed for an electric tankless water heater based on the flow rates of individual fixtures.

Purpose: It helps homeowners and plumbers determine the appropriate size of tankless water heater needed for a home's hot water demands.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Total flow rate (GPM)
• \( Q_i \) — Flow rate of each individual fixture (GPM)

Explanation: The flow rates of all potential simultaneously used fixtures are summed to determine the total demand on the water heater.

3. Importance of GPM Calculation

Details: Proper GPM estimation ensures your tankless water heater can meet peak demand without temperature fluctuations or inadequate flow.

4. Using the Calculator

Tips: Enter the flow rate for each fixture (default values are typical). The calculator sums these to determine the total GPM requirement.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical GPM range for electric tankless heaters?
A: Most residential electric tankless heaters provide 3-8 GPM, with higher-end models reaching up to 10 GPM.

Q2: Should I consider all fixtures or just likely combinations?
A: Consider the maximum possible simultaneous use. For example, shower + kitchen sink + washing machine.

Q3: How do I find my fixtures' GPM?
A: Check manufacturer specs or measure by timing how long it takes to fill a 1-gallon container.

Q4: What if my calculated GPM exceeds available models?
A: Consider installing multiple units or prioritizing fixtures (e.g., don't run dishwasher during showers).

Q5: Does this include temperature rise considerations?
A: No, this is just flow rate. You'll also need to consider the temperature rise needed for your climate.