VA, or volt-ampere is the unit of measurement used to describe UPSes. Wikipedia has a great definition for it.
"While the volt-ampere (abbreviated VA) and the watt are dimensionally equivalent one may find products rated in both VAs and watts with different numbers. This is common practice on UPSs (Uninterrupted Power Supplies). The VA rating is the apparent power that a UPS is capable of producing, while the watt rating is the real power (or true power) it is capable of producing, as opposed to reactive power"
Remember, VA is not the amount of runtime for the UPS.
VA is the capacity of the transformers for the UPS.
More VA means more things you can plug into the unit.
In other words, given the standard 3U 120volt UPS and a 500watt light bulb…
A 3000va UPS will not last any longer than the 2200va UPS.
