1. What is the Furnace Size Calculation?

The furnace size calculation estimates the required heating capacity in BTUs (British Thermal Units) per hour based on the square footage of your house. Proper sizing ensures efficient heating and energy consumption.

2. How Does the Calculator Work?

The calculator uses the furnace size equation:

Where:

• \( BTU \) — British Thermal Units per hour (heating capacity)
• \( Sq Ft \) — Total square footage of the house (ft²)
• \( 40 \) — Standard multiplier for moderate climates

Explanation: This equation provides a basic estimate of furnace size needed to adequately heat a home based on its square footage.

3. Importance of Proper Furnace Sizing

Details: Correct furnace sizing is crucial for energy efficiency, comfort, and system longevity. An oversized furnace will short-cycle, while an undersized one will struggle to maintain temperature.

4. Using the Calculator

Tips: Enter the total square footage of your house in square feet. The calculator will determine the recommended furnace size in BTUs per hour.

5. Frequently Asked Questions (FAQ)

Q1: Why is the multiplier 40?
A: The multiplier of 40 BTU per square foot is a standard estimate for moderate climates. This may vary based on climate zone and home insulation.

Q2: What factors affect furnace sizing?
A: Climate, insulation quality, window efficiency, ceiling height, and home orientation all impact the actual furnace size needed.

Q3: Should I always use this calculation?
A: This is a basic estimate. For precise sizing, consult with an HVAC professional who can perform a Manual J calculation.

Q4: What if I have high ceilings?
A: Homes with high ceilings may require additional heating capacity. Consider increasing the BTU calculation by 10-20% for ceilings over 9 feet.

Q5: How does climate affect furnace size?
A: Colder climates may require 45-50 BTU per square foot, while warmer climates may only need 30-35 BTU per square foot.