Weather stripping

The material applied along the edge of a door or window that is usually flexible and capable of spanning a gap between a door edge and the door casing. The strip of material prevents the entry of air.

Weatherhood

The hood or deflector on a vent opening that is intended to prevent rain water and undesired unconditioned air entry.

Weir

A barrier across a stream of liquid that is used to divert or measure flow per unit of time.

Whisker coils

Whisker coils refers to air conditioning coils where there are no flat plate fins but heat transfer is accelerated by whiskers of metal attached to a tube carrying the liquid used for heating or cooling.

Wolmanized

A trade name of a wood treatment process that renders wood resistant to rot and insect damage.