How much air it needs to move
Compare fans by airflow, the cubic metres of air they move an hour. As a rough guide, around 750 to 1,200 suits a desk, bedside or small room, around 2,000 a living room or open plan office, and 5,000 or more a workshop, garage or warehouse. A fan makes people feel cooler without lowering the room temperature, so more airflow means a stronger breeze that reaches further, not colder air.
Quiet running or high output
Fans with a DC (direct current) motor use from about 1 to 26 watts, offer many speeds and typically start below 30 decibels, quiet enough for a bedroom. Air circulators push a tight column of air that keeps the whole room's air moving, and models that tilt as well as turn spread it up and across the room. Drum and floor fans trade quiet for a powerful blast that reaches across a workshop.
Power, running costs and cleaning
Fans plug straight in with no installation, and the 110 volt drum fans are made for building sites, where tools run from a site transformer. Running costs are low, from a few watts for a DC fan to around 50 watts for a large tower fan and a few hundred for an industrial floor fan, a fraction of what a portable air conditioner draws. Wipe or vacuum the grilles every few weeks, because dust on the blades cuts airflow and adds noise.
