From which location should return air for a forced air furnace generally not be taken?

• A. Basement
• B. Crawl space
• C. Living room
• D. Garage

Answer: (B)

The return air for a forced air furnace should generally not be taken from a crawl space for several reasons. A crawl space is often an unconditioned area that may contain contaminants, humidity, and fluctuating temperatures that can adversely affect indoor air quality and comfort. The air in such spaces may be stale or contain allergens, dust, or moisture, which is not suitable for circulation throughout a living environment.

Returning air from more controlled environments like the basement, living room, or even the garage can provide a more consistent and cleaner air supply. These spaces typically have more regulated temperatures and air quality. However, it's important to ensure proper ventilation in the garage to avoid potential issues with fumes or contaminants. Thus, while those options are generally acceptable, drawing air from a crawl space is not advisable due to the risks associated with using air from a less controlled environment.