The fire broke out at a two-storey house on Ban Pae road in Tambon Tha Sala of Chiang Mai's Muang district.
Five fire engines took about an hour to put out the blaze after it swept through the entire teak-timbered house, engulfing possessions including three vehicles parked in the house compound.
Sunthorn Yamsiri, deputy mayor of Chiang Mai Municipality, said the house owner, Boonnak Thanhikorn, 72, suffered head injuries when she jumped from the second floor to flee the flames.
Police are investigating the cause of the blaze.