Andrew Partington, 27, admitted killing a two-year-old boy after causing a massive explosion in Shaw, Oldham, in June.
The explosion "obliterated" Partington's rented terrace house and two neighbouring homes, with the rest of the row and surrounding streets also left devastated.
Jamie Heaton, 2, had been watching children's TV in the lounge next door and was killed in the blast.
Partington, who was seriously injured in the incident, appeared at Manchester Crown Court by videolink from jail today.
He pleaded guilty to manslaughter and eight charges of destroying neighbouring houses in the blast on Buckley Street, Shaw, Oldham.