Police believe four people carried out the raid, at least one armed with a knife.
It happened at about 9.30pm yesterday (September 20) in Lynton Avenue in the Toller area of the city.
Two women in the house were uninjured, but received medical check-ups at the scene.
Detective Inspector Claire Smith, of Bradford District CID, said: "Enquiries are at an early stage and are continuing today, but we believe there were four suspects and at least one of them had a knife.”
Anyone who witnessed any suspicious activity in the area in the time leading up to, or following the incident can contact Bradford District CID on 101, quoting crime reference 13180470707, or by using the live chat facility on the West Yorkshire Police website.
Information can also be reported anonymously by calling the independent charity Crimestoppers on 0800 555111.