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Ventilation Heat Loss Formula:
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Ventilation heat loss refers to the energy lost when conditioned air escapes from a building and is replaced by outside air. It's a critical factor in residential heating and cooling calculations, affecting both comfort levels and energy efficiency.
The calculator uses the ventilation heat loss formula:
Where:
Explanation: The formula calculates the heat energy loss in BTU per hour based on the volume of air being exchanged and the temperature difference.
Details: Accurate ventilation heat loss calculation is essential for proper HVAC system sizing, energy efficiency assessments, and maintaining comfortable indoor environments while minimizing energy costs.
Tips: Enter CFM (cubic feet per minute of airflow) and delta T (temperature difference in °F). Both values must be valid positive numbers for accurate calculation.
Q1: What does the 1.08 constant represent?
A: The 1.08 constant accounts for the specific heat of air (0.24 Btu/lb·°F) and air density (0.075 lb/ft³) at standard conditions, converted to hourly rate.
Q2: How is CFM measured in residential settings?
A: CFM can be measured using airflow meters, calculated from duct sizing, or estimated based on fan specifications and system design.
Q3: What is a typical delta T for heat loss calculations?
A: Typical delta T values range from 20-70°F depending on climate, with higher values for colder outdoor temperatures.
Q4: How does this relate to overall building heat loss?
A: Ventilation heat loss is one component of total building heat loss, which also includes conduction through walls, windows, and other surfaces.
Q5: Can this formula be used for cooling calculations?
A: Yes, the same formula applies for cooling load calculations, where heat gain occurs when warmer outside air enters the conditioned space.