How do you convert volt-amperes to watts?
An AC circuit has a characteristic called the power factor that determines the relationship between true and apparent power, i.e. the conversion between volt-amperes and wattage. It can vary anywhere from 0.0 to 1.0, but proper designs should be close to 1.0, so often there is little difference between watts and VA. The wattage will always be lower than or equal to the volt-amperes. In the case of devices with significantly low power factors (such as fan motors, which may be around 0.65 when running and as low as 0.1 when first turned on) the wattage may be significantly lower than the volt-amperes, which can be a concern when using watt ratings – one might expect a 960 watt device to draw 8 amps at 120V, but if it had a power factor of 0.65 it would actually draw 12.3 amps. This could be a problem if it was plugged into an outlet on a 10 amp breaker!
