1. What is HVAC Load Calculation?

HVAC load calculation determines the heating and cooling capacity needed for a building. It considers heat transfer through the building envelope (walls, windows, roof), internal heat sources (people, equipment, lighting), and ventilation requirements.

2. How Does the Calculator Work?

The calculator uses the basic HVAC load equation:

Where:

• Envelope Load — Heat transfer through building surfaces (walls, windows, roof)
• Internal Load — Heat generated by occupants, equipment, and lighting
• Ventilation Load — Heat required to condition outside air

Explanation: This simplified calculation sums the three main components of building heat gain/loss to determine the total HVAC system capacity needed.

3. Importance of Load Calculation

Details: Proper load calculation ensures HVAC systems are correctly sized - neither undersized (leading to poor performance) nor oversized (leading to inefficiency and poor humidity control).

4. Using the Calculator

Tips: Enter each load component in BTU/h. For accurate results, these values should come from detailed Manual J calculations or similar professional methods.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between sensible and latent load?
A: Sensible load affects temperature, latent load affects humidity. This calculator shows total load (sum of both).

Q2: How do I get the envelope load value?
A: Envelope load is calculated using building dimensions, insulation values, and temperature differences (Manual J method).

Q3: What's included in internal loads?
A: Occupants (typically 250-400 BTU/person), lighting (3.4 BTU/watt), appliances, and equipment.

Q4: Why is ventilation load important?
A: Outside air must be heated or cooled to indoor conditions, which requires significant energy.

Q5: Is this calculator suitable for final system sizing?
A: This provides a basic estimate. Professional load calculations (Manual J) are recommended for actual system design.