The all-time low interest rate on a 30-year fixed rate mortgage was 3.31% in November 2012. The record high was 18.63% reached in October 1981. With mortgage rates currently between 4.25% and 4.5%, Freddie Mac reports that 123 of 157 metors remain very affordable to households earning the median income. In order for affordability to be hampered in the majority of the markets, interest rates would have to reach 7%, according to Freddie Mac

Tom: Note that the monthly payment for a $200,000 mortgage at the height of interest rates was $3,117, versus a payment of $997 per month for the first quarter of 2014 (and even lower during 2012 and 2013)

Mortgage Rates Through the years (averarge interest rate and  monthly payment on a $200,000 mortgage:

1970's:  8.86 % -  $1,589

1980's: 12.70% -  $2,166

1990's:  8.12%  -  $1.484

2000's:  6.29%  -  $1.237

2014:     4.36%  -  $997