1. What is Combustion Air Opening?

Combustion air opening refers to the required ventilation area needed to provide adequate air for fuel-burning appliances to operate safely and efficiently. Proper combustion air supply is essential for complete fuel combustion and preventing dangerous conditions.

2. How Does the Calculator Work?

The calculator uses the standard combustion air formula:

Where:

• \( Opening \) — Required ventilation area in square inches
• \( BTU/h \) — Total BTU per hour input of all appliances

Explanation: This formula calculates the minimum free area required for combustion air based on the total heat input of the combustion appliances.

3. Importance of Proper Ventilation

Details: Adequate combustion air is crucial for appliance efficiency, safety, and preventing backdrafting, carbon monoxide production, and incomplete combustion.

4. Using the Calculator

Tips: Enter the total BTU/h rating of all combustion appliances in the space. The calculator will determine the required ventilation opening area in square inches.

5. Frequently Asked Questions (FAQ)

Q1: What appliances require combustion air?
A: Furnaces, water heaters, boilers, fireplaces, and any fuel-burning equipment that uses indoor air for combustion.

Q2: Where should combustion air openings be located?
A: Openings should be positioned to provide balanced air supply, typically with one low and one high opening for natural convection.

Q3: Are there different requirements for confined vs. unconfined spaces?
A: Yes, confined spaces (less than 50 cubic feet per 1000 BTU/h) require dedicated combustion air openings.

Q4: What about mechanical ventilation systems?
A: Mechanical air supply systems may have different requirements and should be designed by qualified professionals.

Q5: Do local codes affect these requirements?
A: Always consult local building codes as they may have specific requirements that differ from standard calculations.