After four straight weeks of moving higher, mortgage rates reversed course and headed lower. The average rate on the benchmark 30-year fixed mortgage retreated to 3.8 percent, the lowest since August 1, according to Bankrate.com's weekly national survey. The average 30-year fixed mortgage has an average of 0.4 discount and origination points.

The average 15-year fixed mortgage rate pulled back to 3.03 percent and the larger jumbo 30-year mortgage tied the record low of 4.38 percent. Adjustable mortgage rates were lower, with the 5-year and 7-year ARMs resetting record lows of 2.8 percent and 2.91 percent, respectively.

The minutes of the Federal Reserve's most recent meeting gave investors hope that additional Fed stimulus might be close at hand. All eyes now turn to Jackson Hole, WY for Fed Chairman Ben Bernanke's speech on Aug. 31. If he even hints at forthcoming stimulus, both Treasury yields and mortgage rates will tumble further. Mortgage rates are closely related to yields on long-term government bonds.

The last time mortgage rates were above 6 percent was Nov. 2008. At the time, the average 30-year fixed rate was 6.33 percent, meaning a $200,000 loan would have carried a monthly payment of $1,241.86. With the average rate now 3.8 percent, the monthly payment for the same size loan would be $931.91, a difference of $310 per month for anyone refinancing now.

SURVEY RESULTS

30-year fixed: 3.80% -- down from 3.91% last week (avg. points: 0.4)
15-year fixed: 3.03% -- down from 3.12% last week (avg. points: 0.35)
5/1 ARM: 2.80% -- down from 2.90% last week (avg. points: 0.4)