Average U.S. rates for 30-year and 15-year fixed mortgages fell to record lows for the third straight week. The steady decline has made home-buying and refinancing more affordable than ever for those who can qualify.

Mortgage buyer Freddie Mac says the rate on the 30-year loan dipped to 3.79 percent. That's down from 3.83 percent last week and the lowest since long-term mortgages began in the 1950s.