Transformers are required to handle very high levels of voltage and hence proper insulation is very important in transformers. As of now, the most preferred form of insulation in transformers is cellulose based. The state of cellulose insulation materials like paper & pressboards determines the life end of a transformer. Paper with 1.5% moisture content ages 10 times faster than with only 0.3% moisture. For obvious reasons, it is very important that the moisture is removed from transformer insulation. Vacuum drying has been conventionally used in industries for insulation drying but, as of today the latest technology available is the vapour phase drying process. This paper evaluates the influence of temperatures at various locations on the drying time of the 132kv transformer insulations in vapour phase drying process.