Presidential houses hit by housing crash (© Newscom)

President Barack Obama's Chicago home, with an estimated value of $1.65 million, is down anywhere between 5% to 20% from its peak value, according to Zillow. // © Newscom

U.S. presidents live in worlds about which most mortals can only dream. But if the real-estate market crashes, do their homes continue to float along in a world above, or do they nose dive along with everyone else's?

The answer, it turns out, is mixed.

One thing presidents share with average citizens — the well-heeled sort, anyway — is a liking for setting up family compounds. A story in Forbes' 2010 Investment Guide offers pointers on using trusts to protect such multigenerational properties from taxes and family squabbles.

The research led us to wonder: What's the Kennedys' famed Hyannisport, Mass., compound worth? What about other private homes currently or previously owned by U.S. presidents? And what about the fancy digs Barack and Michelle Obama purchased in 2005, shortly before the housing market crashed?

Assessing the value of such homes is as much an art as a science. There's no way to estimate how much major renovations are worth, for one. Nor is there a way to account for the possibility that a home where a commander in chief slept might set off a bidding war among wealthy history buffs willing to pay a premium. To get a bead on values, Forbes chatted up local real-estate agents, sifted through comparable sales and looped in valuations from Zillow.com, a real-estate data firm in Seattle.

What's your home worth?

It turns out that a few presidential houses appear to have shed value during the downturn. The homes are listed here.

What of the Obama's former digs? The damage done by the economic mess to the value of the Obamas' home is surprisingly minimal. Discounting renovations that the couple undertook, and the increase in value from purchasing a slice of neighboring land from convicted fraudster Tony Rezko, the president's Chicago home is worth around $1.65 million, estimates real-estate agent Beki Darin of Prudential Rubloff Properties in Chicago.

Slide show:  5 presidential homes going south

That's down from the peak the leafy Kenwood enclave on Chicago's South Side enjoyed in early 2008. Just how much it's down is debatable, however. Zillow's data suggest the home's value is off 20%, but Darin says a 5% dip is more like it.

The $1.65 million figure is also right in line with what the Obamas paid in 2005. (The couple was assailed by critics who accused them of ethical lapses in purchasing the home and slice of adjacent land at cost from a known political fundraiser.) As support for her estimate, Darin points at other recent sales of Kenwood mansions. Seven $1-million-plus sales have taken place in the 60615 ZIP code this year, including a $1.4 million sale of the house next door to the Obama home, at 5040 S. Greenwood Ave. (That house was similar in size to the Obamas' but needed renovation.)

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A real-estate agent who handled the sale of the house to the Obamas disagrees strongly with Darin's math. Donna M. Schwan of MetroPro Realty says the presidential couple's home would sell for $2.2 million today, even before accounting for renovations. Throw those in, Schwan says, and the Obamas are owners of a $3 million house.

Schwan may have a bit of propensity for toppish valuations. Back in 2005, she and her client were asking 18% more than what the Obamas paid for their house. But she's no doubt right that extra land and renovations have boosted the value of the Obamas' home. Even accepting Darin's more conservative estimate, it's clear the Obamas haven't suffered the fate of many others who bought homes near the peak of Chicago's housing boom. Prices in the Windy City are down an average of 25% to 30% from peak levels.

(It's worth noting that values of mansions in Kenwood may have further to fall. Seven are on the market now, and buyers have been soaking up only one per month. The seven-month inventory qualifies as a glut. Even the Obamas' neighbors at 5040 S. Greenwood had to settle for an offer 20% below their original asking price.)

Back on the East Coast, the Barnstable, Mass., tax assessor this year cast a cold hard look at the historic Cape Cod compound owned by the family of late President John F. Kennedy. There are three major properties in the 6-acre compound. The most coveted is one that was used by the late Joseph Kennedy, the original family patriarch, at 50 Marchant Ave. The 21-room, 7,500-square-foot structure sits on 2.4 acres of picture-perfect Nantucket Sound waterfront. The other two homes, at 111 Irving Ave. and at 28 Marchant Ave., are roughly 4,000 square feet each.

Alas, even Camelot has off days. The Barnstable tax appraiser recently estimated the combined value of the three homes at $11.2 million, down $3 million from their peak. Two veteran real-estate agents in the area agree.

"Values here are down 25% to 30%," says Amy Massey-Weider, who runs the Century 21 Shoreland real-estate brokerage in nearby Hyannis. The news is glum for owners, perhaps, but good for those who dream of buying a little slice of the shores where Kennedys frolic.

"It's absolutely an excellent time to buy, based on where values and interest rates are," Massey-Weider says.

The lower values aren't all bad news for the Kennedy clan. The family has shown no interest in selling any of its homes. Meantime, the Kennedys' property tax bill came to $118,400 in 2009, which was down $9,000 from the previous year. (There are other Kennedy homes in and around Hyannisport. If you want to become a neighbor, Massey-Weider and Diana Silvester, the other agent with whom we spoke, can direct you.)

If you want to buy a home where a president actually slept, that's possible, too. When President Harry S. Truman left office, he retreated to his hometown of Independence, Mo., where he and his wife, Bess, lived in her family's home. That structure has since been converted into a museum. Truman's formative years, however, were spent in a home in Independence at 909 W. Waldo Ave. It went up for sale in May for a mere $365,000.

That's $115,000 more than the owners, Paul and Rita Nolan, paid for the historic home in July 2007, when the economy was jumping. Why the price jump? Paul Nolan, a mechanical systems designer, poured $110,000 in labor and materials into the house, he explains.

"It's been renovated five or seven times since it was built, but it's never been restored," Nolan says. "We carted 18 truckfuls of junk out and only brought in two." He was so concerned with getting the restoration right that he insisted on using a hand saw when he made cuts to the home's original wood, and he saved every square-head nail he pulled out along the way.

The results are impressive. But Nolan's college-age son doesn't see it that way. "He won't stay here because he thinks the house is old and creepy," Nolan says. "I guess when it comes to history, you have to be one of those folks who gets it."