1. What is an 8 GPM Electric Tankless Water Heater?

Definition: This calculator determines the required flow rate for an electric tankless water heater sized for large households in northern climates.

Purpose: It helps homeowners and plumbers properly size tankless water heaters to ensure adequate hot water supply.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The total flow rate is the sum of all simultaneous hot water demands in the household.

3. Importance of Proper Sizing

Details: An 8 GPM unit is recommended for large homes (3+ bathrooms) in cold climates to ensure sufficient hot water during peak demand.

4. Using the Calculator

Tips: Enter the number of fixtures and average flow per fixture (default 1.0 GPM). For accurate results, use actual fixture flow rates.

5. Frequently Asked Questions (FAQ)

Q1: Why is 8 GPM recommended for northern climates?
A: Colder incoming water requires more heating capacity to reach desired temperatures.

Q2: What fixtures should be included?
A: Include all fixtures that might run simultaneously (showers, faucets, appliances).

Q3: How does temperature rise affect sizing?
A: Greater temperature rises (colder climates) reduce effective capacity - thus needing higher GPM ratings.

Q4: What electrical requirements are needed?
A: 8 GPM units typically require 240V and significant amperage (often 100A+ dedicated circuit).

Q5: Can multiple units be used?
A: Yes, some installations use multiple units in parallel for higher demand situations.