1. What is the Tankless Water Heater Calculator?

The Tankless Water Heater Calculator estimates the required flow rate (in gallons per minute) for tankless water heaters in the USA based on fixture usage. It helps determine the appropriate size of tankless water heater needed for your household.

2. How Does the Calculator Work?

The calculator uses the equation:

Where:

• \( gpm \) — Gallons per minute flow rate
• \( us\_fixture\_gpm \) — Flow rate of US fixtures (gal/min)

Explanation: The equation calculates the total flow rate by summing up the flow rates of all fixtures that may be used simultaneously.

3. Importance of GPM Calculation

Details: Accurate GPM calculation is crucial for selecting the right size tankless water heater to ensure adequate hot water supply for simultaneous fixture usage.

4. Using the Calculator

Tips: Enter the total flow rate of US fixtures in gallons per minute. The value must be valid (greater than 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is GPM important for tankless water heaters?
A: GPM determines the flow rate capacity needed to supply hot water to multiple fixtures simultaneously without temperature fluctuations.

Q2: What are typical GPM requirements for households?
A: Typical requirements range from 2-5 GPM for small apartments to 7-10 GPM for larger homes with multiple bathrooms.

Q3: How do I calculate total fixture GPM?
A: Add up the GPM ratings of all fixtures that might be used at the same time (showers, sinks, appliances).

Q4: Are there limitations to this calculation?
A: This provides a basic estimate. Actual requirements may vary based on water temperature rise needed and specific fixture types.

Q5: Should I consider future expansion?
A: It's recommended to add 20-25% capacity for future needs or occasional high-demand situations.