1. What is an Electric Tankless Hot Water Heater Calculator?

Definition: This calculator estimates the required flow rate (GPM) for an electric tankless water heater based on fixture flow rates in your home.

Purpose: It helps homeowners and plumbers properly size an electric tankless water heater to meet household hot water demands.

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

Explanation: The calculator sums the flow rates of all potential simultaneously used fixtures to determine the peak demand.

3. Importance of Proper Sizing

Details: Correct sizing ensures adequate hot water supply, prevents overloading the electrical system, and optimizes energy efficiency.

4. Using the Calculator

Tips: Enter the flow rate for each fixture in your home. Default values are provided based on standard fixture flow rates.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical flow rate needed for a whole house?
A: Most homes require 6-8 GPM, but this depends on the number of bathrooms and fixtures.

Q2: How do I know my fixture flow rates?
A: Check manufacturer specs or use standard values (provided as defaults in the calculator).

Q3: Should I consider simultaneous use?
A: Yes, the calculator sums all fixtures that might be used simultaneously (e.g., shower + kitchen sink).

Q4: What temperature rise should I account for?
A: This calculator focuses on flow rate. You'll need to consider your incoming water temperature and desired output temperature separately.

Q5: How many amps will an 8 GPM unit require?
A: Typically 100-150 amps at 240V, but exact requirements depend on the specific model and temperature rise needed.