1. What is a Home Heat Load Calculator?

Definition: This calculator estimates the heat energy required to maintain a comfortable temperature in a building based on heat loss through surfaces and air infiltration.

Purpose: It helps HVAC professionals and homeowners properly size heating systems for optimal efficiency and comfort.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Total heat load (Watts)
• \( U \) — U-value of building elements (W/m²K)
• \( A \) — Surface area of building elements (m²)
• \( \Delta T \) — Temperature difference between inside and outside (Kelvin)
• \( Q_{inf} \) — Heat loss from air infiltration (W)

Explanation: The calculator sums heat loss through all surfaces (U × A × ΔT) and adds infiltration heat loss.

3. Importance of Heat Load Calculation

Details: Accurate heat load calculation ensures proper heating system sizing, energy efficiency, and prevents under/over heating.

4. Using the Calculator

Tips: Enter U-value (thermal transmittance), surface area, temperature difference, and infiltration heat loss. For multiple surfaces, calculate each separately and sum the results.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls: 0.2-0.3 W/m²K. Older uninsulated walls: 1.0-1.5 W/m²K.

Q2: How do I find ΔT (temperature difference)?
A: Subtract the coldest expected outdoor temperature from your desired indoor temperature.

Q3: What's included in infiltration heat loss?
A: Heat lost through air leaks, ventilation, and door openings. Can be estimated using air changes per hour.

Q4: Should I include all surfaces in the calculation?
A: Yes, include walls, roof, floor, windows, and doors with their respective U-values and areas.

Q5: Does this account for heat gains?
A: No, this calculates heat loss only. For complete analysis, consider solar gains and internal heat sources.