“Seven people were killed, one was severely injured and three others lightly wounded,” Naser Atabati said on Saturday.
The official added that the house in Shahriar neighborhood was flattened by the force of the blast.
Late on Friday, an Iranian teenager making homemade fireworks for a festival ahead of the Persian New Year blew up his home, killing himself and six other family members.
The dead were five teenagers and a middle-aged couple.
Fireworks and bonfires traditionally mark the last Wednesday of the Persian year, a fire festival known as Chaharshanbeh-Soori.
This year, the Persian New Year, or Nowruz, falls on Tuesday, March 21.
Every year, authorities launch public awareness campaigns about the dangers of fireworks. During last year's festival, three people were killed and more than 2,500 injured.
This year's publicity campaign has also called for “respect” for 16 firefighters who were martyred battling a blaze in a Tehran high-rise in January.