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Heater Size Formula:
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BTU/h (British Thermal Units per hour) is a measurement of heat energy transfer. It indicates how much heat a heater can produce in one hour. One BTU is the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit.
The calculator uses the simple formula:
Where:
Explanation: This basic calculation assumes standard ceiling height (8 feet) and moderate climate conditions. For more precise calculations, additional factors like insulation quality, window size, and climate zone should be considered.
Details: Proper heater sizing is crucial for energy efficiency and comfort. An undersized heater will struggle to maintain temperature, while an oversized one will cycle on/off frequently, wasting energy and potentially creating uncomfortable temperature swings.
Tips: Measure your room's length and width in feet, then multiply to get square footage. Enter this value in the calculator. For irregularly shaped rooms, divide into rectangles and calculate each section separately.
Q1: What if my ceilings are higher than 8 feet?
A: For higher ceilings, multiply the result by (ceiling height ÷ 8). For example, with 10-foot ceilings: BTU/h × (10/8) = adjusted BTU/h.
Q2: Does this work for all climate zones?
A: This uses a standard multiplier (35) for moderate climates. Use 45-50 for colder climates or 20-25 for warmer areas.
Q3: What about room insulation?
A: Poor insulation may require 10-20% more BTU/h, while excellent insulation may need 10-20% less.
Q4: Should I round up the result?
A: It's generally recommended to round up to the nearest available heater size for better performance.
Q5: Can I use this for whole-house heating?
A: For whole-house systems, professional Manual J calculations are recommended as they account for many additional factors.