Xantrex Technology RS3000 - Manual (Page 115)

Terminology
975-0170-01-01 C–5
Watt Hour (W/h)
Electrical power measured over a period of time. One watt hour of
electricity is equivalent to one watt of power being consumed for
one hour. A 3-watt light operated for 2 hours would consume
6 Wh (watt hour) of electricity.
Volt-amps
(VA)
A measure of the “apparent” power equivalent to the true power
(watts) in resistive loads, but exceeding watts in non-resistive
loads. VA is calculated by multiplying volts times amps without
using power factor.