(Duluth Patch) – A smoke detector that may have saved the lives of six people in Gwinnett County Tuesday morning was installed by firefighters three years ago as an effort to make sure more residents have smoke alarms.

Gwinnett County Fire Chief Russell Knick said firefighters installed the smoke detector in December 2016 at the house on Dogwood Street, according to the Atlanta Journal Constitution.

The residents, who were asleep when the fire started in the basement of the one-story house, were awakened by the smoke detector’s alarm, Capt. Tommy Rutledge said.

The home is a total loss and the cause of the fire is undetermined, he said, but the five adults and one child escaped unharmed.

Lt. Aaron Blackwell, whose crew installed the smoke detector, said the residents were appreciative Tuesday, despite the loss of their home, according to the AJC.

“They had smiles on their faces,” he said. “It’s very satisfying.”

Crews were dispatched at 3:40 a.m. and gained control of the fire by 4:34 a.m., but were still working to put out flames early Tuesday, according to Gwinnett fire officials.

Gwinnett County firefighters responded to a report from an occupant that said the basement of their single-story home on Dogwood and Jones Streets was on fire.