1. What is Furnace BTU Sizing?

Furnace BTU sizing calculates the appropriate heating capacity needed for a house based on its square footage and climate factors. Proper sizing ensures efficient heating without energy waste or insufficient heating capacity.

2. How Does the Calculator Work?

The calculator uses the furnace sizing formula:

Where:

• \( House Sq Ft \) — Total square footage of the house (ft²)
• \( Factor \) — BTU per square foot per hour (BTU/ft²/hr)
• \( BTU/hr \) — British Thermal Units per hour required

Explanation: The factor typically ranges from 30-60 BTU/ft²/hr depending on climate, insulation quality, and house characteristics.

3. Importance of Proper Furnace Sizing

Details: Correct furnace sizing is crucial for energy efficiency, comfort, and system longevity. Oversized furnaces cycle frequently, reducing efficiency, while undersized units struggle to maintain temperature.

4. Using the Calculator

Tips: Enter total house square footage and select an appropriate BTU factor (30 for well-insulated homes in mild climates, 60 for poorly insulated homes in cold climates).

5. Frequently Asked Questions (FAQ)

Q1: Why is the BTU factor range 30-60?
A: This range accounts for different climate zones and insulation levels. Colder climates and poorer insulation require higher factors.

Q2: What factors affect BTU requirements?
A: Climate zone, insulation quality, window types, ceiling height, and house orientation all impact heating requirements.

Q3: Should I use the high or low end of the range?
A: Use lower values (30-40) for newer, well-insulated homes in mild climates. Use higher values (50-60) for older homes or cold climates.

Q4: Is this calculation sufficient for final furnace selection?
A: This provides a rough estimate. Professional Manual J calculations are recommended for precise sizing.

Q5: What about multi-story homes?
A: Use total square footage of all heated floors. Consider zoning for multi-story homes with significant temperature variations.