For a blower type furnace, how many square inches of free air are required per 1,000 BTU of the furnace's rated capacity?

The requirement for free air intake for a blower type furnace is crucial for ensuring proper combustion and operation. For every 1,000 BTU of the furnace's rated capacity, a standard guideline indicates that 2 square inches of free air are necessary. This requirement helps maintain adequate airflow, which is essential for both efficiency and safety.

This measurement ensures that there is enough air for the combustion process to occur correctly and optimally, preventing issues such as incomplete combustion or overheating. Adequate airflow is vital for the furnace's blower to function effectively and to avoid any strain that could lead to equipment failure or safety hazards in operation. Therefore, following this guideline helps provide a safe and efficient heating environment.