A router would be different though. It would keep the same radius regardless of building geometry as it's signal degrades with physical distance from its antenna.

A dehumidifier works by running air through it and removing moisture then exhausting the now dry air out. The dry air would then intermix back into the room's air, lowering it's total humidity level. It may take a little more time based on the turbidity of the rooms air, but a dehumidifier would have the capacity to dry a .25x20x24m the same as a 3x5x8m room as both contain the same amount of air in their 120m³.

Edit: added units