Power Factor - This is the factor that can vary from 0 to 1 which, when multiplied by the Apparent Power (volt-amperes) of an a-c circuit, gives the Real Power (watts). The power factor is abbreviated (pf). Thus, for an a-c circuit, one a-c volt times one a-c ampere x pf equals watts (a-c Watts = a-c Volta x a-c Amperes x pf).
Demand - This is an expression used frequently in the sale or purchase of electric power. Demand is the amount of electric power (kilowatts or kw) used for a given time interval. Usually, demand is determined for a 15-minute time interval. It should be recognized that regardless of how seldom a large electric load is used, the power company has to have that amount of power available whenever the load is applied. The time interval is refered to as the demand interval.