If you plan on staying in your house for the next 30 years or to the term of the loan, you can calculate the value of your loan based on current rates. I spelled out the steps to show the value of the loan in a post at

http://www.mrmoneymustache.com/forum/investor-alley/paying-off-mortgage-early-how-bad-is-it-for-your-fi-date/ . Financial institutions are required to calculate the asset or liabilities of their loans in a similar fashion. As a consumer, a loan is primarily an asset, because if the the loan interest rate is higher than market for the most part you can refinance and get a lower rate and reset the loan. Where a bank if you have a 30 year fixed rate loan can not come back to you and force you to pay a higher rate. So their loans to you are valued at higher or lower than the actual principal owing based on the current interest rates vs. your locked in rate, calculated based on expected actual term vs. ie a 30 year term.

Here is the quote/calculation from that post:

"US Mortgage Interest rates had the largest increase in 38 years last week.

http://www.fool.com/investing/general/2013/06/27/weekly-mortgage-rates-rise-most-in-38-years.aspxThose that have a 30 year fixed rate mortgage in the 3.xx increased their networth on the value of their mortgage. The value of your locked in cheap loan is an asset as long as you keep it to term. You can calculate the NPV of the loan with your interest rate and the market's interest rate to determine how much you have made.

To calculate the value of your gain,

1) Calculate or obtain the Principal and Interest on your current mortgage payment

2) Figure out what the current interest rate a similar loan at current rates.

3) Go to this website or your favorite NPV website

http://www.pine-grove.com/online-calculators/present-value-annuity-calculator.htm4) Enter your monthly P&I payment as calculated or known in step 1:

5) Enter today's mortgage interest rate as indicated in step two as the annaul discount rate.

6) Fill out the term and other information and calculate.

7) Take Present Value as calculated and subtract your current loan balance

8) The difference is the NPV gain or loss on your loan vs. the current rates.

IE: $450,000 30 year fixed at 3.5% locked where interest rates are now at 4.5%, I left it with no payments made for simplicity sakes even though the 3.5% rates were easier to obtain a few months ago. The value of your cheap loan is :

$450,000 Loan Balance

($397,086) Present value of the the monthly mortgage payments at 4.5%

$52,914 gain

If your PP, stocks or others are down. Maybe your interest rate hedge(30 year fixed Rate Mortgage) kicked off a gain this week. This works in reverse as well if interest rates drop, but they have been at historical lows so the downside risk is probably on the lower end of the spectrum.

Don't prepay your mortgage if you have a low 30 year fixed mortgage. Enjoy the interest rate hedge.

Tom"