Ceiling Fan Size Calculator

Blade span is matched to room area — roughly 75 cm for a small room and up to 152 cm for a large one. Long rooms need two fans rather than one larger one.

No. It moves air across skin, which speeds evaporation and makes people feel cooler. The air temperature is unchanged, and the motor adds a small amount of heat.

At least 2.1 m above the floor for clearance, and 25 to 30 cm below the ceiling so it can draw air in properly. Mounted too close to the ceiling it moves far less than its rating.

Reversed and slow, so it pushes air up and displaces warm air down the walls without creating a draught. Running it forward in winter simply makes people feel colder.

Cubic feet per minute of airflow. It matters more than blade span for actual performance, since blade pitch and motor speed vary considerably between fans of the same diameter.

Yes. Since it cools people rather than air, a fan running in an empty room only uses electricity and adds motor heat.

Very little — a typical fan draws tens of watts, a fraction of an air conditioner. That is the case for using one to raise the tolerable thermostat setting in summer.

One with a DC motor, which uses substantially less power than an AC motor for the same airflow and usually offers more speed steps and quieter running. It costs more up front.

Usually blade imbalance or a loose mounting. A balancing kit corrects blade imbalance; a wobble that persists after balancing is a mounting problem and worth fixing properly.

Yes, and it is efficient — the air movement lets the thermostat sit a couple of degrees higher for the same comfort, which saves considerably more than the fan uses.

Enough to bring the blades 25 to 30 cm below the ceiling and at least 2.1 m above the floor. High ceilings need a longer downrod to put the airflow in the occupied zone.

On a covered porch, yes, using a fan rated for damp or wet locations. The air movement also discourages mosquitoes, which are weak fliers.