Heat Loss Calculator for Heat Pumps

Heat Loss Formula:

\[ Q = \sum (U \times A \times \Delta T) \]

Heat Loss (W):

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1. What is a Heat Loss Calculator for Heat Pumps?

Definition: This calculator estimates the heat loss of a building based on U-values, surface areas, and temperature differences.

Purpose: It helps HVAC professionals and homeowners properly size heat pumps for efficient heating.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = \sum (U \times A \times \Delta T) \]

Where:

\( Q \) — Heat loss (Watts)
\( U \) — U-value (W/m²K, thermal transmittance)
\( A \) — Surface area (m²)
\( \Delta T \) — Temperature difference between inside and outside (Kelvin)

Explanation: The calculator multiplies the U-value by surface area and temperature difference to determine heat loss through that surface.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations ensure properly sized heat pumps that operate efficiently without short cycling or insufficient heating.

4. Using the Calculator

Tips: Enter the U-value (lower is better insulation), surface area of the element, and design temperature difference. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls: 0.15-0.30 W/m²K, older uninsulated walls: 1.0-1.5 W/m²K.

Q2: How do I calculate total heat loss for a house?
A: Calculate heat loss for each building element (walls, roof, floor, windows) separately and sum them.

Q3: What temperature difference should I use?
A: Use your design temperature (e.g., if you want 20°C inside and -5°C is your coldest expected outside temp, ΔT=25K).

Q4: Does this include air infiltration losses?
A: No, this calculates fabric heat loss only. Air changes should be calculated separately.

Q5: How much should I oversize my heat pump?
A: Typically 10-20% above calculated heat loss to account for extreme conditions and defrost cycles.