A neighbour rescued two children from a window ledge on the first floor of a burning house at Ordnance Close in Feltham on Friday afternoon.
The children were lowered to safety before fire crews arrived and were unhurt.
Firefighters wearing breathing apparatus rescued a woman from the first floor of the house. She was taken to hospital by the London Ambulance Service suffering from smoke inhalation.
The fire began on the ground floor, which was slightly damaged.
A London Fire Brigade spokesperson said:
“The property was fitted with a smoke detector, but the battery was missing. It is very important that you don’t remove smoke detector batteries for any other uses in the home. It is essential that you have a working smoke alarm. Smoke alarms provide vital early warning and buy you extra time to escape if there is a fire.”
Two fire engines and around 12 firefighters and officers from Feltham Fire Station in London and Staines Fire Station in Surrey attended the incident.
The Brigade was called at 1614 and the fire was under control at 1640.
The cause of the fire is under investigation.