1. What Is Tankless Water Heater Sizing?

Tankless water heater sizing involves calculating the required flow rate (GPM) based on peak simultaneous hot water demand and flow-based sizing factors to ensure adequate hot water supply for all household needs.

2. How Does The Calculator Work?

The calculator uses the tankless water heater sizing formula:

Where:

• \( GPM \) — Gallons per minute required
• \( \text{Peak Demand} \) — Number of fixtures running simultaneously
• \( \text{Flow-based sizing factor} \) — Flow rate adjustment factor based on fixture types

Explanation: This calculation ensures your tankless water heater can handle maximum hot water demand during peak usage times.

3. Importance Of Proper Sizing

Details: Proper sizing is crucial for energy efficiency, consistent hot water supply, and preventing system overload. Undersized units lead to cold water surprises, while oversized units waste energy.

4. Using The Calculator

Tips: Count all fixtures that might run simultaneously during peak usage (showers, sinks, dishwasher, etc.). Use appropriate flow factors based on fixture types and local water pressure.

5. Frequently Asked Questions (FAQ)

Q1: What is considered peak demand?
A: Peak demand refers to the maximum number of hot water fixtures that might be used simultaneously during busy household hours.

Q2: How do I determine flow-based sizing factors?
A: Factors vary by fixture type - typical showers use 1.5-2.5 GPM, sinks 0.5-1.5 GPM, dishwashers 1-2 GPM.

Q3: What happens if I undersize my tankless water heater?
A: Undersizing leads to inadequate hot water, temperature fluctuations, and system shutdown during peak demand.

Q4: Should I consider temperature rise in sizing?
A: Yes, temperature rise (difference between incoming and desired water temperature) significantly affects required GPM capacity.

Q5: Are there regional variations in sizing requirements?
A: Yes, groundwater temperature, water pressure, and local building codes can affect sizing calculations.