For a 200,000 BTU input appliance, the required combustion air is how many cubic feet?

For a 200,000 BTU input appliance, the required combustion air is how many cubic feet?

• A. 5,000
• B. 10,000
• C. 15,000
• D. 20,000

Answer: (B)

The required combustion air for an appliance that draws air from the room is based on a simple rule: provide 50 cubic feet of room air for every 1,000 BTU per hour of the appliance’s input. This ensures there’s enough oxygen for complete combustion and helps prevent negative pressure or backdrafting. For a 200,000 BTU/hr appliance, you divide 200,000 by 1,000 to get 200, then multiply by 50. That equals 10,000 cubic feet of room volume needed to supply combustion air. Thus, the required combustion air is 10,000 cubic feet. If the appliance were directly vented to the outdoors or supplied with outdoor air, the calculation would differ, but for indoor-air combustion air, 10,000 ft^3 is the standard requirement.

The required combustion air for an appliance that draws air from the room is based on a simple rule: provide 50 cubic feet of room air for every 1,000 BTU per hour of the appliance’s input. This ensures there’s enough oxygen for complete combustion and helps prevent negative pressure or backdrafting.

For a 200,000 BTU/hr appliance, you divide 200,000 by 1,000 to get 200, then multiply by 50. That equals 10,000 cubic feet of room volume needed to supply combustion air.

Thus, the required combustion air is 10,000 cubic feet. If the appliance were directly vented to the outdoors or supplied with outdoor air, the calculation would differ, but for indoor-air combustion air, 10,000 ft^3 is the standard requirement.