Three fire engines and around 15 firefighters were called to a fire at a house on Clarendon Road in Notting Hill.
A small part of the third floor of a semi-detached house was damaged by fire. Firefighters wearing breathing apparatus led two people to safety who were treated on scene after suffering from smoke inhalation.
The Brigade's Fire Investigators believe the fire was caused by sunlight coming through a window, which was refracted by a reflective surface and ignited nearby materials.
A London Fire Brigade spokesperson said:"The sun is especially strong during these summer months but fires caused by refracted sunlight can happen all year round and are actually quite common.
"Our advice is to make sure that you keep mirrors, crystals, glass ornaments and other reflective items out of direct sunlight at all times.”
"It's also really important to make sure that you have a working smoke alarm on every level of your home."
The Brigade was called at 0733 and the fire was under control by 0755. Fire crews from North Kensington and Paddington fire stations attended the scene.