The gas-fed fire ravaged the two-story wood frame house on Colfax Avenue at the corner of Ashwood Avenue and extended to the garage, responders said.
No injuries were immediately reported.
The fire broke out around 1 a.m. and went to two alarms within minutes.
Downed wires complicated the situation for firefighters.
The fire, which could be seen from the nearby northbound Garden State Parkway was placed under control around 2:40 a.m. but rekindled nearly seven hours later.
Click here to follow Daily Voice Mahwah-Ramsey and receive free news updates.