It happened shortly after 3:00 am at a home on Woodrow and Grove Avenues.
Firefighters arrived to find heavy smoke coming from the structure. The blaze started in a detached garage that was converted into an apartment.
The residents heard their smoke detector go off and were able to get out of the house safely.
No one was hurt.
The fire did not extend into the home.
Officials are working to determine the cause of the blaze.