1. What is a Navien Water Heater Sizing Calculator?

Definition: This calculator determines the required flow rate (GPM) for a Navien tankless water heater based on fixture flow rates.

Purpose: It helps HVAC professionals and homeowners properly size Navien tankless water heaters for optimal performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GPM \) — Gallons per minute required
• \( \text{Fixtures Flow} \) — Total flow rate of all fixtures (gal/min)

Explanation: The total flow rate of all simultaneously used fixtures determines the minimum GPM capacity needed for the water heater.

3. Importance of Proper Water Heater Sizing

Details: Correct sizing ensures adequate hot water supply, energy efficiency, and prevents overworking the unit.

4. Using the Calculator

Tips: Enter the total flow rate of all fixtures that might run simultaneously. The value must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine fixtures flow?
A: Add up the flow rates (GPM) of all fixtures that might be used simultaneously (showers, faucets, appliances).

Q2: What's a typical flow rate for fixtures?
A: Standard shower: 2.5 GPM, faucet: 1.5 GPM, dishwasher: 1.5 GPM, washing machine: 2.0 GPM.

Q3: Should I add a safety factor?
A: Navien recommends adding 20% to the calculated GPM for optimal performance.

Q4: How does temperature rise affect sizing?
A: Higher temperature rises reduce the maximum GPM capacity. Consult Navien's performance charts.

Q5: Can I use this for commercial applications?
A: This calculator is for residential use. Commercial applications require professional assessment.