For years, investors and homeowners alike have tried to call the bottom in the housing market. So far, home prices haven't cooperated. But looking at the way that home buyers have behaved recently reveals some insight into what the future of housing may look like -- and where you should concentrate your attention when it comes to investing.

A tale of two housing markets
You don't have to look hard to find dour indicators of just how bad off the housing industry is right now. Just last week, government data came out on February sales of new homes, which dropped to a record low annualized rate of just 250,000. Looking back over the past 12 months, only 349,000 new homes sold, which was also a record low. The inventory of new homes for sale rose to nearly nine months.

Source: Census Bureau.

The continuing weakness in new home sales has weighed on the stocks of homebuilders for a long time. Although Toll Brothers (NYSE: TOL), Lennar (NYSE: LEN), and KB Home (NYSE: KBH) have seen some share gains in recent months, they still trade well below their highs from five years ago, as the housing boom came to an end.

Yet despite the attention that new home sales receive, they really represent only a small portion of overall sales. Similar figures on sales of existing homes, while still weak, aren't nearly as pessimistic. The corresponding numbers for February showed an annual sales rate of 4.88 million existing homes, with 8.6 months of supply in the inventory of existing homes for sale as inventory began its annual rise in preparation for the spring sales season. That's well off the highs of around 7 million during the housing boom, but it also represents a big rebound from lows below 4 million in the middle of last year.

Source: National Association of Realtors.

Looking for value?
The typical conclusion to draw from the supremacy of existing home sales over new homes focuses on what homeowners have to do before putting their homes up for sale in a buyer's market for housing. With prospective buyers able to pick the cream of the crop, sellers competing with each other have to renovate their homes to make the cut, driving up business at Home Depot (NYSE: HD), Lowe's (NYSE: LOW), and Lumber Liquidators (NYSE: LL). Indeed, some of the more hopeful predictions for these stocks rely on continuing interest in renovating rather than an outright rebound in housing overall.

That conclusion makes it seem as if the current state of the housing industry is just cyclical and that eventually new home sales will rebound. But looking at consumer behavior in an entirely different industry -- auto sales -- suggests a more overarching trend.

Lately, used-car prices have risen to record high levels, even as new-car sales have remained low. With cash-strapped car buyers struggling to make ends meet, saving even a small amount on a good-condition used car makes more sense than paying up for a new one. Though counterintuitive, this has actually helped Ford (NYSE: F) and General Motors, because even with somewhat weak sales, the upward pressure on used-car prices has also supported new-car prices, allowing them to keep margins relatively high.

If that phenomenon repeats itself in the housing industry, what you should look for first is for existing home prices to rise. Only once that happens will homebuilders be in a position to benefit -- but the benefits may come sooner than you'd expect if you just look at raw data on new home sales.

The right move in real estate
With home prices for existing and new homes still low, perhaps the best way to profit from the housing downturn is simply to buy real estate directly. If you can afford the time and expense involved, you can take advantage of high inventory and weak demand to get the home of your dreams -- or a big prospective moneymaker.

But if you prefer to invest passively, the time isn't ripe for homebuilding stocks yet. Until market conditions change, homebuilders will continue rising and falling in fits and starts.

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Fool contributor Dan Caplinger is glad to have a roof over his head. He doesn't own shares of the companies mentioned in this article. General Motors, Home Depot, and Lowe's are Motley Fool Inside Value selections. Lumber Liquidators is a Motley Fool Rule Breakers recommendation. Ford is a Motley Fool Stock Advisor selection. Motley Fool Options has recommended writing covered calls on Lowe's. The Fool owns shares of Ford and Lumber Liquidators. Motley Fool Alpha LLC has written calls on KB Home, which is a Motley Fool Big Short short-sale recommendation. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool's disclosure policy gives you shelter.