A good rule of thumb is to keep smoke detectors ___ feet away from air diffusers, ceiling fans, etc.

• A. 2
• B. 6
• C. 3
• D. 10

Answer: (C)

Smoke detectors rely on the air around them to bring in smoke particles so they can sense danger. If a diffuser, vent, or ceiling fan creates a strong air current, it can push smoke away from the sensor or create drafts that trigger false alarms. Placing the detector about three feet away from these air movers avoids direct air streams while still keeping the detector within the area where smoke would typically reach it early in an incident.

If you place it too close, like two feet, you still risk being in the direct draft and may get nuisance alarms or miss early smoke due to air being blown away. If you place it much farther away, like six or ten feet, the room’s smoke might not reach the sensor quickly enough for a timely warning. Three feet strikes the right balance for reliable and prompt detection.