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Combustion Air Formula:
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Combustion air refers to the amount of air required for proper and safe operation of gas-fired water heaters. Adequate air supply ensures complete combustion and prevents dangerous conditions.
The calculator uses the combustion air formula:
Where:
Explanation: This formula calculates the minimum free area needed to provide adequate combustion air for gas-fired water heaters based on their BTU input rating.
Details: Proper combustion air is essential for safe water heater operation. Insufficient air can lead to incomplete combustion, carbon monoxide production, reduced efficiency, and potential safety hazards.
Tips: Enter the BTU/h rating of your water heater (found on the manufacturer's label). The calculator will determine the required free area for combustion air in square inches.
Q1: What is free area for combustion?
A: Free area refers to the unobstructed opening size that allows air to flow into the combustion area, typically measured in square inches.
Q2: Where should combustion air openings be located?
A: Openings should be positioned to draw air from outside or from well-ventilated spaces, following local building codes and manufacturer specifications.
Q3: Are there different requirements for confined vs unconfined spaces?
A: Yes, confined spaces (closets, small rooms) have stricter requirements and often need dedicated combustion air ducts from outside.
Q4: What if my water heater is in a garage?
A: Garages require special consideration to prevent ignition of flammable vapors. Combustion air must be drawn from outside, typically 12 inches above floor level.
Q5: Does this calculation meet all code requirements?
A: This provides a basic calculation. Always consult local building codes, manufacturer instructions, and qualified professionals for specific installation requirements.