Do I need a fan?
Air movement created by fans and air movers increases the rate of evaporation and gives the best chance of ensuring all of the wet area benefits from dry air. While the dehumidifiers themselves push dry air out at pressure, thereby creating a bit of airflow, optimum drying will ensure there’s good airflow around wet areas, taking saturated air back to the dehumidifier to be dried.
As a rough guide, at the early stages of flood restoration increasing air velocity from 0.5 metres per second to 3.5 metres per second would double the evaporation rate, with a further doubling of the evaporation rate by increasing air movement to 7.0 metres per second.