1. What is an AC BTU Size Calculator?

Definition: This calculator estimates the cooling capacity needed for an air conditioning unit based on room area, heat load per square foot, and adjustment factors.

Purpose: It helps homeowners and HVAC professionals properly size air conditioning units for optimal efficiency and comfort.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Cooling load (BTU/h)
• \( A \) — Area to be cooled (ft²)
• \( \text{BTU/ft}^2 \) — Heat load per square foot (BTU/h·ft²)
• \( F \) — Adjustment factor for special conditions

Explanation: The area is multiplied by the base cooling requirement per square foot, then adjusted for factors like insulation, sunlight, and occupancy.

3. Importance of Proper AC Sizing

Details: Correct sizing prevents energy waste, ensures proper dehumidification, and extends equipment life. Oversized units short-cycle while undersized units run constantly.

4. Using the Calculator

Tips: Enter the room area in square feet, base BTU requirement (default 20 BTU/h·ft²), and adjustment factor (default 1.0). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical BTU/ft² value?
A: Most rooms need 20 BTU/h per square foot, but this varies from 15 (well-insulated) to 30 (sunny/poorly insulated).

Q2: When should I adjust the factor?
A: Increase to 1.1-1.3 for sunny rooms, kitchens, or high occupancy. Decrease to 0.8-0.9 for shaded or well-insulated spaces.

Q3: How do I measure the area?
A: Multiply room length by width. For irregular rooms, divide into rectangles and sum the areas.

Q4: What about room height?
A: For ceilings over 8 feet, add 10% per additional foot. The calculator assumes standard 8-foot ceilings.

Q5: How do I convert BTU to tons?
A: Divide BTU by 12,000 (1 ton = 12,000 BTU/h). A 24,000 BTU unit = 2 tons.