Trillions of dollars in American home equity have vanished. And experts don't expect many home values to recover before 2015. What about your home? Analyzing data and calculations from various sources can give you an idea of how much home equity you have (or haven't) lost, and when you can expect to recover.

Home Equity in America: How Long Before Your Home Recovers its Value?

Research firm First American CoreLogic recently released a report that contained some bad news about the housing market outlooks for those living in five US metro areas. They are, from worst to slightly less worse:

• Detroit, Michigan
• Las Vegas, Nevada
• Lancaster, Pennsylvania
• Fort Meyers, Florida
• Pittsburgh, Pennsylvania

According to First American CoreLogic's mortgage amortization calculations and housing price data, the average homeowners in these areas can expect to be underwater on their properties until at least 2020.

Home Equity Havens: No Housing Busts Here

Other regions skipped the housing boom and sidestepped the housing bust as well. Home buyers in these didn't overpay for homes a couple of years ago and for the most parts they aren't underwater today. These states are:

• Montana
• North Dakota
• Nebraska
• Iowa
• Oklahoma
• Indiana
• North Carolina
• Kentucky
• Alabama
• Hawaii
• New York State

You're probably in great shape if you live in Vermont (for which there was no home equity data available), West Virginia, or Wyoming--according to foreclosure research firm RealtyTrac, these states have some of the lowest foreclosure rates in the country.

How Fast Can Your Home Equity Recover?

The formula used by First American CoreLogic is straightforward enough for anyone to use. The researchers assumed that nationwide, home values will increase at a rate of 3% per year (a very conservative estimate by most accounts; many investment pros use a 4% to 5% figure and, according to the National Association of Realtors, the historical average real estate appreciation in the US is 6.8%). The researchers assume that mortgages are paid down at a rate of about 3.3% per year.

You can be much more accurate because you have more specific information. Your home equity situation depends on when you bought your property, how much you put down on your new home, if you refinanced your mortgage, if you've done any home improvements, and what sort of mortgage you have. Input your mortgage information into a mortgage amortization calculator and see what your balance will be in a year.

You can estimate your home's value today with one of a number of online real estate sites. Then, multiply that number by 1.03. Compare it to your expected mortgage balance a year from now. If the mortgage balance is greater than your home's expected value, run your value calculation again--take the new property value and multiply it again by 1.03. Then, look at your mortgage amortization schedule and compare your mortgage balance at the end of year two with your property value at the end of year two. Do this as many times as it takes until you find the year in which your property value exceeds your loan balance. That's when you can expect to be above water on your home loan.

Not All Gloom and Doom: 75% of the Country's Housing Is Okay

What gets lost in all the noise is that the worst of the housing crisis has been confined to a handful of states. Three-quarters of American properties are not under water. And decreased housing prices, tax breaks, and low interest rates have created unprecedented opportunity for many to buy new homes for the first time.

You may have all the home equity you need for a mortgage refinance. Run some numbers and make sure that you aren't passing up potential savings.