1. What is an AO Smith Water Heater Sizing Calculator?

Definition: This calculator determines the appropriate size (in gallons) for an AO Smith water heater based on peak demand and first hour rating.

Purpose: It helps homeowners and plumbers select the right water heater size to meet household hot water needs efficiently.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Size \) — Recommended water heater size (gallons)
• \( Peak Demand \) — Maximum hot water usage during peak hour (gallons)
• \( First Hour Rating \) — Efficiency factor (default 0.75 for residential)

Explanation: The peak demand is multiplied by the first hour rating to determine the appropriate tank size.

3. Importance of Proper Water Heater Sizing

Details: Correct sizing ensures adequate hot water supply while maximizing energy efficiency and minimizing operating costs.

4. Using the Calculator

Tips: Enter your peak hot water demand in gallons and the first hour rating (default 0.75). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my peak demand?
A: Calculate your household's maximum hot water usage during the busiest hour (showers, laundry, dishes, etc.).

Q2: What's a typical first hour rating?
A: For residential use, 0.75 is common. Commercial applications may use higher values.

Q3: When would I change the first hour rating?
A: Adjust for high-efficiency models (lower rating) or commercial applications (higher rating).

Q4: Does this account for simultaneous use?
A: Yes, if your peak demand calculation includes all simultaneous hot water needs.

Q5: How does this differ for tankless heaters?
A: Tankless heaters are sized by flow rate (GPM) rather than tank capacity.