1. What is a Heat Pump Water Heater Size Calculator?

Definition: This calculator estimates the appropriate size (in gallons) for a heat pump water heater based on peak hour demand and a sizing factor.

Purpose: It helps homeowners and professionals properly size heat pump water heaters for optimal efficiency and performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Size \) — Required water heater size (gallons)
• \( Peak\,Hour\,Demand \) — Maximum hot water usage in peak hour (gallons)
• \( Factor \) — Sizing factor (typically 0.7 for heat pump water heaters)

Explanation: The peak hour demand is multiplied by a factor that accounts for the heat pump's recovery rate and efficiency.

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 hour hot water demand in gallons and the sizing factor (default 0.7). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my peak hour demand?
A: Calculate the total hot water used during your busiest hour (showers, appliances, etc.) or use standard estimates (e.g., 30-40 gallons per person).

Q2: Why is the factor lower for heat pump water heaters?
A: Heat pump water heaters have slower recovery rates but higher efficiency, requiring a smaller tank size relative to demand.

Q3: When would I change the sizing factor?
A: Adjust if you have unusual usage patterns, very high efficiency models (factor 0.6), or hybrid systems (factor 0.8).

Q4: What's typical for a family of four?
A: For a peak demand of 50 gallons, a 35-40 gallon heat pump water heater is typically sufficient (50 × 0.7 = 35).

Q5: Does this account for simultaneous use?
A: Yes, if your peak hour demand accurately reflects your maximum simultaneous usage.