The victims, four men and a woman, were tenants of the 14-room house which was reduced to ashes.
The fire broke out yesterday evening when only those five persons were present in the house, the officials said.
The cause of the fire and the extent of damage were being ascertained.
Deputy Commissioner Kemo Lollen said fire tenders stationed at the Advanced Landing Ground of the Indian Air Force were pressed into service to douse the blaze.
Khandu asked people to follow fire safety measures especially during the winter so that such incidents do not recur as the administration can intervene in the aftermath.
Unconfirmed reports said the owner of the house was also among the dead.