1. What is Furnace Size Calculation?

Furnace size calculation determines the appropriate heating capacity needed for a house based on its square footage. 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:

• \( BTU \) — British Thermal Units per hour (BTU/h)
• \( Sq Ft \) — Total square footage of the house
• \( 30-60 \) — BTU factor per square foot

Explanation: The BTU factor ranges from 30-60 based on climate, insulation quality, and house characteristics. Lower factors for well-insulated homes in mild climates, higher factors for poorly insulated homes in cold climates.

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 and lifespan. Undersized furnaces cannot maintain comfortable temperatures.

4. Using the Calculator

Tips: Enter total square footage of your house and select appropriate BTU factor based on your climate and insulation quality. Square footage must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: What BTU factor should I use?
A: Use 30 for well-insulated homes in mild climates, 45 for average insulation and climate, 60 for poorly insulated homes in cold climates.

Q2: Is this calculation accurate for all homes?
A: This provides a basic estimate. Professional Manual J calculation considers windows, doors, insulation, and local climate for precise sizing.

Q3: What if my house has high ceilings?
A: For ceilings over 8 feet, multiply square footage by (ceiling height ÷ 8) before calculation.

Q4: Does this work for multi-story homes?
A: Yes, use total square footage of all heated floors combined.

Q5: What about heat loss through windows?
A: This calculation assumes average window coverage. Homes with large window areas may need higher BTU factors.