An elderly woman had to be rescued following a house fire in Cambridge.

Firefighters were called to Dundas Street North around 10:30 p.m. on Wednesday after the resident returned home and found heavy smoke inside their unit.

When crews responded they rescued an 87-year-old woman from one of the front units before extinguishing the flames in one of the rear units.

Platoon Chief Rick Hembly with the Cambridge Fire Department says the cause is likely electrical as there were a number of extension cords in use throughout the home.

The elderly woman declined an ambulance and was taken away by a family member.

There are four units inside the building; the fire affected one unit and the three others sustained minor smoke damage.

Damage is estimated at $25,000 and the investigation is ongoing at this time.