1. What is HVAC Load Calculation?

HVAC load calculation determines the heating and cooling capacity needed to maintain comfortable conditions in a building. It accounts for heat transfer through building envelope, internal heat gains from occupants and equipment, and other factors.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( Area \) — Building area in square feet
• \( U \) — Overall U-value of building envelope (BTU/(h·ft²·°F))
• \( \Delta T \) — Design temperature difference between inside and outside (°F)
• \( Occupants \) — Number of people in the space
• \( Equipment \) — Electrical equipment wattage
• \( Lighting \) — Lighting load in BTU/h

Explanation: The calculation sums heat transfer through building envelope with internal heat gains from occupants, equipment, and lighting.

3. Importance of Load Calculation

Details: Proper load calculation ensures HVAC systems are correctly sized - neither undersized (inadequate comfort) nor oversized (short cycling, poor efficiency).

4. Using the Calculator

Tips: Enter accurate building parameters. For precise calculations, professional Manual J calculations are recommended.

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 estimates total sensible load.

Q2: How accurate is this simplified calculation?
A: It provides a rough estimate. For actual system design, use Manual J or other professional methods.

Q3: What's a typical U-value for residential buildings?
A: Modern homes might be 0.05-0.10 BTU/(h·ft²·°F), older homes 0.15-0.30 or higher.

Q4: Why convert equipment watts to BTU/h?
A: 1 watt = 3.412 BTU/h, as all electrical energy eventually converts to heat.

Q5: What about ventilation loads?
A: This simplified calculator doesn't account for ventilation air. ASHRAE standards specify ventilation requirements.