The male victim who was at home asleep had a pillow placed over his face and was punched before the suspects left with a quantity of jewellery items.
The crime took place at Langdale Gardens in Perivale just before 4pm on Thursday (March 3).
Police are appealing for witnesses who may have seen or heard anything which caused suspicion at the time to come forward.
Two suspects are described as light-skinned black man, aged in their 20s or 30s, and of average build.
The first suspect had a stubble goatee, was around 5ft 8ins in height and was wearing a black tracksuit top which had a white line down the arm and black tracksuit bottoms.
Suspect number two is around 5ft 7ins in height and was wearing a black tracksuit top, black tracksuit bottoms and white trainers.
Officers believe there may be a third suspect, a black male who is younger than the other two suspects.
Anyone with information should call CID officers at Acton via 101, or call Crimestoppers anonymously on 0800 555 111.