Phuket City Police were informed of the fire, on Pracha Samakkee Rd in Ratsada, at 12:20am.
Firefighters were dispatched to the scene, where they worked for approximately an hour and a half to bring the blaze under control.
The homeowner, Chuleerat Saewong, was found in shock and was taken by emergency responders to Vachira Hospital.
Patipol Phromma, 23, Ms Chuleerat’s son, told officers he was sleeping on the second floor, as was his mother, when the fire started.
He said he was unaware of the cause but was alerted by a neighbour who reported hearing an explosion-like sound from the ground floor before seeing smoke.
Authorities are currently investigating the cause of the fire.