1. What is an HVAC Heat Load Calculator?

Definition: This calculator estimates the heat load in BTUs (British Thermal Units) required for proper HVAC system sizing.

Purpose: It helps HVAC professionals and homeowners determine the appropriate heating or cooling capacity needed for a space.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( BTUs \) — Total heat load (BTU/hr)
• \( Area \) — Square footage of the space (sq ft)
• \( BTUsPerSqFt \) — Base heating/cooling factor (BTU/sq ft)
• \( WindowBTUs \) — Additional load from windows (BTU/hr)
• \( OccupantBTUs \) — Heat generated by occupants (BTU/hr)

Explanation: The base load is calculated from area, then adjusted for window heat gain/loss and occupant heat generation.

3. Importance of Heat Load Calculation

Details: Proper heat load estimation ensures efficient HVAC operation, prevents system over/under sizing, and maintains comfort levels.

4. Using the Calculator

Tips: Enter the area in square feet, base BTUs per sq ft (default 20), and any additional loads from windows or occupants. All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical BTU per sq ft value?
A: For cooling, 20 BTU/sq ft is standard. For heating in cold climates, 30-40 BTU/sq ft may be needed.

Q2: How do I calculate window BTUs?
A: Multiply window area by 20 BTU/sq ft (south-facing) or 15 BTU/sq ft (other directions).

Q3: What's the BTU contribution per person?
A: About 400 BTU/hr per person for light activity, up to 1000 BTU/hr for vigorous activity.

Q4: Should I include other factors?
A: For precise calculations, consider appliance heat, insulation levels, and ceiling height.

Q5: How does this relate to AC tonnage?
A: 12,000 BTU/hr = 1 ton of cooling capacity. Divide total BTUs by 12,000 to get required tons.