1. What is an ASHP Heat Loss Calculator?

Definition: This calculator estimates the heat loss of a building to help properly size an air source heat pump (ASHP) system.

Purpose: It helps homeowners and HVAC professionals determine the heating capacity needed for efficient operation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat loss (Watts)
• \( U \) — U-value of building element (W/m²·K)
• \( A \) — Surface area (m²)
• \( \Delta T \) — Temperature difference between inside and outside (°C)

Explanation: The formula calculates how much heat escapes through a building element based on its insulation properties, size, and temperature difference.

3. Importance of Heat Loss Calculation

Details: Proper heat loss estimation ensures correctly sized heat pumps for optimal efficiency, comfort, and system longevity.

4. Using the Calculator

Tips: Enter the U-value (thermal transmittance), 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/m²·K. Older walls: 1.0-1.5 W/m²·K.

Q2: How do I find the temperature difference?
A: Subtract your local winter design temperature from desired indoor temperature (typically 20-22°C).

Q3: Should I calculate for each building element?
A: Yes, calculate separately for walls, roof, floor, windows, then sum for total heat loss.

Q4: What about air infiltration?
A: Add 10-20% to the total heat loss or use 0.33 × volume × air changes × ΔT.

Q5: How does this relate to ASHP sizing?
A: Total heat loss at design temperature should match the ASHP's heating capacity at that temperature.