Three fires — one of which left seven people homeless — kept Honolulu firefighters busy Friday night and yesterday.

The most substantial fire occurred at 3:46 a.m. yesterday in Wai'anae when a single-family home on Plantation Road was destroyed. Firefighters were able to bring the fire under control by 4:30 a.m., fire Capt. Robert Main said.

Three adults and four children were displaced by the fire and are receiving Red Cross assistance.

Damage was estimated at $550,000. The cause was under investigation.

Hours earlier, at 11:40 p.m. Friday, firefighters responded to a single-family home on Farrington Highway in Nanakuli and doused a fire limited to one room.

The cause of the blaze was a discarded cigarette, Main said. Damage was estimated at $2,000.

The third fire occurred yesterday at a business on Pupukahi Street in Waipahu.

The alarm came in at 1:58 p.m. Main said the cause of the fire was arson. The building's exterior was damaged; damage is estimated at $2,000.