1. What is an Electric Tankless Water Heater Flow Rate Calculator?

Definition: This calculator estimates the total flow rate (GPM) needed for an electric tankless water heater by summing the flow rates of all fixtures that might run simultaneously.

Purpose: It helps homeowners and plumbers determine the appropriate size for tankless water heaters based on expected hot water demand.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The flow rates of all fixtures that might be used simultaneously are added together to determine the total required flow rate.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures your tankless water heater can provide enough hot water for simultaneous uses without temperature fluctuations.

4. Using the Calculator

Tips: Enter the flow rate for each fixture (default values are typical for residential use). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical flow rate for electric tankless water heaters?
A: Most residential units provide 3-8 GPM, with electric models typically in the 3-5 GPM range.

Q2: Should I include all fixtures in my home?
A: Only include fixtures that might run simultaneously. For example, a shower and kitchen sink, but not two showers if you never use them together.

Q3: What if my calculated flow exceeds my heater's capacity?
A: Consider a larger unit, multiple units, or staggering hot water use during peak times.

Q4: How do I find my fixtures' flow rates?
A: Check manufacturer specs, look for flow restrictors (often marked), or measure with a bucket and stopwatch.

Q5: Does this account for temperature rise requirements?
A: No, this calculates flow rate only. Temperature rise depends on inlet water temperature and heater capacity.