What is the rule of thumb for additional combustion air needed?

The correct answer is based on the general guideline for calculating the amount of additional combustion air required for gas appliances. According to this rule of thumb, for every 1,000 BTUs of gas consumption, an additional 50 cubic feet of air is needed to ensure that the combustion process is efficient and safe. This guideline helps prevent issues such as improper combustion, which can lead to dangerous conditions including carbon monoxide buildup.

By following this guideline, it becomes easier to assess whether existing ventilation is sufficient for gas appliances or whether more air supply is necessary. The specified ratio ensures optimal combustion and overall appliance performance. This rule is especially important in enclosed spaces where air circulation may be limited, thereby emphasizing its relevance in ensuring safety and effectiveness in the operation of combustion appliances.