A grey Audi A4 was stolen after a burglar entered the home in Moorside Avenue, Smithills, and took car keys from a coat on a banister.
The theft happened while a 31-year-old man, who owns the car, was inside the house, between 4.20pm and 6.20pm on Tuesday.
A woman, also aged 31, who lives in the home, said: “People need to be aware that these people will come into homes even when they know somebody is in. When you come home you don’t automatically lock the front door. You don’t expect something like this to happen.
I didn’t expect someone would enter my house in the day. What would they have done if they had seen my partner in the house? They wouldn’t have been bothered.”
She said her family will no longer leave doors unlocked despite people coming home around the same time of day.
The car, registration FV08 UXG, has not been recovered.
Anyone with information should call police on 101.