1. What is HVAC Load Calculation?

HVAC load calculation determines the heating and cooling capacity needed for a space. It accounts for heat transfer through building envelope (conduction), air leakage (infiltration), and heat generated by occupants and equipment (internal gains).

2. How Does the Calculator Work?

The calculator uses the basic HVAC load formula:

Where:

• \( Conduction \) — Heat transfer through walls, roof, windows (BTU/h)
• \( Infiltration \) — Heat loss/gain from air leakage (BTU/h)
• \( Internal Gains \) — Heat from people, lights, equipment (BTU/h)

Explanation: This simplified version sums the major components of heat transfer to estimate the total HVAC capacity needed.

3. Importance of HVAC Load Estimation

Details: Proper load calculation ensures HVAC systems are correctly sized - preventing energy waste from oversized systems or inadequate comfort from undersized systems.

4. Using the Calculator

Tips: Enter all components in BTU/h. For detailed calculations, use Manual J methods. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between this and Manual J calculation?
A: This is a simplified version. Manual J provides detailed room-by-room calculations accounting for all building characteristics.

Q2: How do I get conduction values?
A: Calculate using U-values × area × temperature difference, or use rule-of-thumb values based on construction type.

Q3: What are typical internal gain values?
A: Approximately 400 BTU/h per person, plus equipment and lighting loads (varies by usage).

Q4: Should I add a safety factor?
A: Professional calculations typically add 10-20% safety factor for extreme conditions.

Q5: How does this relate to tonnage?
A: 12,000 BTU/h = 1 ton of cooling capacity. Divide total BTU/h by 12,000 to estimate required tonnage.