Electric Tankless Water Heater Calculator

Electric Tankless Water Heater Formula:

\[ kW = Q \times \Delta T \times 0.1467 \]

Required Power (kW):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Electric Tankless Water Heater Calculator?

The Electric Tankless Water Heater Calculator determines the required kilowatt (kW) capacity for an electric tankless water heater based on flow rate and desired temperature rise. This helps in selecting the properly sized unit for your hot water needs.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ kW = Q \times \Delta T \times 0.1467 \]

Where:

\( kW \) — Required power in kilowatts
\( Q \) — Flow rate in gallons per minute (GPM)
\( \Delta T \) — Temperature rise in degrees Fahrenheit (°F)
\( 0.1467 \) — Conversion factor

Explanation: The formula calculates the energy required to heat water based on flow rate and temperature difference, with 0.1467 being the conversion factor that accounts for the specific heat of water and unit conversions.

3. Importance of kW Calculation

Details: Proper sizing is crucial for electric tankless water heaters. Undersized units won't provide enough hot water, while oversized units waste energy and increase costs. Accurate kW calculation ensures optimal performance and energy efficiency.

4. Using the Calculator

Tips: Enter the desired flow rate in GPM and the temperature rise needed (difference between incoming cold water temperature and desired hot water temperature). Typical temperature rises range from 40°F to 70°F depending on climate and usage.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical flow rate for household fixtures?
A: Shower: 1.5-2.5 GPM, Kitchen faucet: 1.0-2.2 GPM, Bathroom faucet: 0.5-1.5 GPM. Total flow rate should be calculated based on simultaneous usage.

Q2: How do I determine the temperature rise needed?
A: Subtract your incoming cold water temperature from your desired hot water temperature. Incoming water temperature varies by season and location (typically 40-60°F).

Q3: What if I need to run multiple fixtures simultaneously?
A: Add the flow rates of all fixtures that might be used at the same time and use that total flow rate in the calculation.

Q4: Are there any safety factors I should consider?
A: It's recommended to add 10-20% to the calculated kW to account for heat loss and ensure adequate performance during peak demand.

Q5: Can this calculator be used for gas tankless water heaters?
A: No, this calculator is specifically for electric units. Gas tankless water heaters use different sizing calculations based on BTU requirements.