1. What is a Tankless Water Heater Size Calculator?

Definition: This calculator estimates the required flow rate (in gallons per minute) for sizing a tankless water heater based on your home's fixture demands.

Purpose: It helps homeowners and plumbers determine the appropriate size tankless water heater needed to meet simultaneous hot water demands.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The flow rates of all potentially simultaneous fixtures are summed to determine the peak demand your tankless heater must handle.

3. Importance of Proper Sizing

Details: Correct sizing ensures adequate hot water supply during peak usage while avoiding oversizing which wastes energy and money.

4. Using the Calculator

Tips: Enter the flow rates for each fixture in your home. Default values are provided for typical fixtures. All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical flow rate for showers?
A: Standard showerheads use 2.5 GPM, while low-flow models use 1.5-2.0 GPM.

Q2: How do I find my fixture flow rates?
A: Check manufacturer specs or measure by timing how long it takes to fill a 1-gallon container.

Q3: Should I include all fixtures in my home?
A: Only include fixtures that might run simultaneously during peak usage times.

Q4: What temperature rise should I consider?
A: This calculator determines flow rate only. Consider a separate calculation for temperature rise requirements.

Q5: How much extra capacity should I add?
A: Consider adding 10-20% to the calculated flow rate for future needs or occasional high demand.