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Unit Heater Sizing Formula:
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Unit heater sizing involves calculating the appropriate heating capacity (in BTU/hr) required to effectively heat a given space. Proper sizing ensures efficient operation and optimal comfort while avoiding energy waste.
The calculator uses the unit heater sizing formula:
Where:
Explanation: This formula calculates the heat loss based on the volume of air to be heated and the temperature difference that needs to be maintained.
Details: Correct unit heater sizing is crucial for energy efficiency, occupant comfort, and system longevity. Oversized heaters cycle frequently, reducing efficiency, while undersized heaters cannot maintain desired temperatures.
Tips: Enter the volume of the space in cubic feet and the temperature difference in °F. Ensure accurate measurements for reliable results. Consider additional factors like insulation quality and air infiltration for real-world applications.
Q1: What is ΔT in heater sizing?
A: ΔT represents the temperature difference between the desired indoor temperature and the outdoor design temperature for your location.
Q2: How do I calculate room volume?
A: Multiply length × width × height of the space in feet to get cubic feet (ft³).
Q3: What is the 0.018 coefficient?
A: This is the heat loss coefficient for air, representing the BTU required to heat one cubic foot of air by one degree Fahrenheit.
Q4: Should I add a safety factor?
A: Yes, typically add 10-20% to the calculated BTU requirement to account for unusual heat loss and ensure adequate heating capacity.
Q5: What other factors affect heater sizing?
A: Insulation quality, window area, ceiling height, building orientation, and local climate conditions all impact actual heating requirements.