According to Freddie Mac’s weekly mortgage rate survey, for 13 straight weeks, the average 30-year fixed rate mortgage has held below 4.000% for mortgage applicants willing to pay up to 0.8 discount points plus a full set of closing costs.

These are the lowest mortgage rates in history and now — with a bevy of loan programs for the nation’s 11 million “underwater homeowners” including HARP, the FHA Streamline Refinance, and the VA IRRRL — millions of U.S. homeowners can exploit the current mortgage rate environment.

In this 4-minute clip from NBC’s The Today Show, you’ll learn about today’s mortgage market and your refinancing opportunities.

The video begins by telling us that 14 million credit-worthy Americans have yet to refinance their respective mortgages, and are leaving an average of $471 in “wasted savings” on the table each month which adds up to more than $5,600 annually.

That’s a big number.

Some of the video’s other key points include :

• Refinancing is “worth the hassle” when mortgage rates are as low as they are today
• The best rates are reserved for homeowners with the highest credit scores
• Comparison shop — your current mortgage lender may not offer you the best rates

Furthermore, the video reveals the characteristics of the homeowner type most likely to benefit from a refinance. These traits include having with 20% equity in the home; have plans to live in the home for at least the next 36 months; carrying a current mortgage rate of 5 percent or higher.

It should also be added that, with a zero-closing-cost or low-closing-cost mortgage, even a small reduction in your mortgage rate can make a refinance worthwhile.

Mortgage rates are low but can’t stay low forever. If you haven’t participated in the Refi Boom, talk with a loan officer and review your mortgage options. You may be able to save hundreds of dollars per month with just modest closing costs.