The police identified the deceased as Abdul Karim, 48, his wife Afroj, 45, their daughters Ishrat, 18, Reshma, 16, and Afsana, 8, and son Abdush Shakur, 12.
Karim was a migrant labourer from West Bengal and was living with his family in a one-room rented accommodation.
Panipat superintendent of police Shashank Kumar Sawan said the incident took place at 6.30am when food was being cooked.
A fire tender was rushed to the spot, while the room was reduced to ashes within minutes.
The bodies were sent for post-mortem and Karim’s extended family in West Bengal was informed.