Home
Back
BTU Calculation Formula:
| From: | To: |
The Furnace Size Calculator helps determine the appropriate British Thermal Unit (BTU) capacity needed for heating a space based on square footage and climate factors. Proper furnace sizing is essential for efficient heating and energy conservation.
The calculator uses the standard BTU calculation formula:
Where:
Explanation: The BTU factor ranges from 30 for mild climates to 60 for very cold climates, accounting for regional temperature variations and insulation quality.
Details: Correct furnace sizing ensures optimal energy efficiency, consistent comfort, and prevents issues like short cycling (oversized) or inadequate heating (undersized). Proper sizing also extends equipment lifespan and reduces energy costs.
Tips: Enter the total square footage of your space and select the appropriate BTU factor based on your climate zone. Consider additional factors like ceiling height, insulation quality, window efficiency, and local climate conditions for more precise results.
Q1: What happens if my furnace is oversized?
A: Oversized furnaces short cycle (turn on/off frequently), reducing efficiency, increasing wear, and creating temperature fluctuations.
Q2: What BTU factor should I use for my area?
A: Use 30 for southern regions, 40 for central states, 50 for northern areas, and 60 for extreme cold climates like Alaska or high mountains.
Q3: Should I consider other factors besides square footage?
A: Yes, consider ceiling height, insulation quality, window types, number of occupants, and local climate for accurate sizing.
Q4: What's the difference between BTU and BTUh?
A: BTU measures energy, while BTUh (BTU per hour) measures heating capacity. Furnace sizes are typically rated in BTUh.
Q5: Is professional assessment recommended?
A: For final furnace selection, consult with HVAC professionals who can perform Manual J calculations for precise sizing.