A kilowatt hour is calculated by adding the watts together and deviding by 1000, this will give you kilowatts (kW). Then work out how many hours you are using this load for. multiply the kW by the...
KVA (kilovoltamperes) is KW (kilowatts) divided by sin(90 - theta) where theta is the phase angle between voltage and current. This answer assumes a sinusoidal, linear load.