What is the difference between W (Watts) and VA (Volt-Amps)?
For many items the two are identical however for some computer equipment the two can differ, VA ratings always being equal or higher than the W rating. The ratio of W to VA is known as the Power Factor (often represented as a decimal or percentage). This information is hard to come by even on your equipment. The best guidelines offered are: if your equipment was made since the mid 1990s it has been Power Factor Corrected meaning its W = VA. These (post mid 1996) larger computer equipment, routers, switches, and servers have a PF of 1. Personal computers, their accessories and small hubs have a PF of less than 1 (0.65). Generally it is a good idea not to exceed either the W or the VA rating. We use Watt ratings.
