When firefighters arrived at the home in the 2100 block of Northeast Second Street shortly before 3 p.m., heavy smoke was billowing out of the house, said Boynton Beach Fire Rescue Capt. Kevin Quinn.
No one was injured in the fire, but there was "pretty heavy damage" to the house, Quinn said.
The American Red Cross was called to the home to assist five adults and two children with shelter and clothes. The cause of the fire was not known Sunday night.
Doreen Frankson, who lives next door to the house, said she was just coming back from church when she saw the fire engines on the street. She later walked over to see the damage.
"It's horrible, horrible," Frankson said. "They didn't save anything in there. It was just burned up."
A day earlier, Palm Beach County firefighters extinguished a fire on the 9400 block of Verona Lakes Boulevard west of Boynton Beach about 5:30 p.m.
A heavy electrical load in one room of the house was the source of the fire, which caused $100,000 in damage. The homeowner had three computer systems and several extension cords running through the room, fire officials said. There were no injuries.