Which insect is most likely to be found in a furnace room?

The answer is most likely to be firebrats. These insects prefer warm, moist environments and are commonly found in areas such as furnace rooms, where the temperature is elevated and can provide the humid conditions they thrive upon. Firebrats are especially attracted to areas that have a consistent heat source, making furnace rooms an ideal habitat for them.

In contrast, while silverfish can occasionally be found in warm spaces, they are not as specifically linked to furnaces and typically prefer slightly more humid areas, like bathrooms or basements. Granary weevils are primarily associated with food storage areas and grain products rather than warm, dry environments. Clothes moths tend to infest wool and similar materials, and although they can survive in various environments, they do not have the same preference for warm, humid areas as firebrats do.