1. What is a Water Heater Efficiency Calculator?

Definition: This calculator estimates the current efficiency of a water heater based on its rated efficiency, degradation rate, and age.

Purpose: It helps homeowners and professionals assess water heater performance over time and determine when replacement might be needed.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \eta \) — Current efficiency (%)
• Rated Efficiency — Manufacturer's original efficiency rating (%)
• \( D \) — Degradation rate (decimal per year)
• Age — Age of water heater (years)

Explanation: The calculator accounts for normal efficiency degradation that occurs over time in water heaters.

3. Importance of Efficiency Calculation

Details: Monitoring efficiency helps estimate energy costs, environmental impact, and when replacement becomes cost-effective.

4. Using the Calculator

Tips: Enter the rated efficiency (typically 90% for modern heaters), degradation rate (default 0.02/year), and heater age. All values must be valid.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical degradation rate for water heaters?
A: Most water heaters degrade at 1-3% per year (0.01-0.03 in decimal).

Q2: How do I find my water heater's rated efficiency?
A: Check the EnergyGuide label or manufacturer specifications (usually 90% for modern gas heaters).

Q3: When should I consider replacing my water heater?
A: When efficiency drops below 70% or the unit is over 10 years old.

Q4: Does this account for water hardness or maintenance?
A: No, these factors may accelerate degradation beyond the standard rate.

Q5: Why does zip code matter for water heater efficiency?
A: Water hardness and incoming water temperature vary by location, affecting performance.