Former State Sen. Vincent J. Fumo, who is trying to sell his mansion for $5.5 million, thinks his property tax is too high - even though his bill for next year says the house is worth just $953,500.

But his latest appeal didn't sway Philadelphia's property-tax board. With two staunch Fumo allies absent, the Board of Revision of Taxes (BRT) decided yesterday not to lower its market value on Fumo's home, a converted convent in the Spring Garden section.

The decision means Fumo will owe $25,215 in property tax next year, nearly four times his current bill.

"The board has maintained all along that its decision on the value of Sen. Fumo's property was appropriate," said the board's spokesman, Kevin Feeley.

The seven-member board, which hears testimony in public but makes decisions in private, voted against Fumo without dissent, according to sources familiar with the decision.

Joseph C. Bright, the attorney who handled Fumo's appeal, did not respond to requests for comment.

Fumo is on trial on federal charges of using state and nonprofit money for his own benefit, in part to renovate the 27-room home.

The trial was suspended yesterday afternoon after Fumo complained of dizziness and was taken to Hahnemann University Hospital.

The board's struggle over Fumo's tax started in 2007, when he put the house up for sale at $7 million to raise money for his defense. He has since dropped his price.

The 12,000-square-foot home, which Fumo purchased in 1994, has a spa in the back garden, seven fireplaces, an elevator, a shooting range, heated sidewalks, a wine cellar and a roof deck. "No expense was spared," the real estate listing says.

From 2003 until last year, the city said the home's market value was just $250,000. The board's assessors said that was an accident; computer programs had missed Fumo's house because it was so unusual, they said.

Yesterday, Bright said Fumo thought some increase was fair.

"The taxpayer would be willing to live with an increase - but not a fourfold increase," the attorney told board members during the hearing.

He argued that Fumo was being singled out in an illegal "spot assessment."

The argument didn't impress Russell Nigro, a former state Supreme Court justice and ex-Fumo ally. He said Fumo hadn't complained when tax assessors missed him year after year.

"I'm a little flabbergasted that someone would have numerous years of non-increases in assessments and then walk in here and say this is a spot assessment," Nigro said.

Board members asked Bright and Fumo's appraiser, Reaves C. "Trip" Lukens III, how much they thought the former senator's house was worth.

Bright said he had no idea. Lukens said he had never been inside it.

"With all due respect to the seller, I think he's been overoptimistic," Bright said.

Instead, they argued, Fumo's assessment was wrong because the board's values all over Philadelphia are completely out of whack.

Lukens said his analysis showed that the board's assessed, taxable values for residential property were, on average, just 9 percent of what they should be - not 32 percent, the number applied under the city's complicated assessment formula.

The tax board is trying to scrap that system and come up with new property values to reflect what homes are worth on the market, but this "actual-value" effort has been troubled by delays and cost overruns.

Fumo's assessment has roiled the normally low-profile BRT. In October 2007, after publicity about Fumo's big asking price and low assessment, member Robert N.C. Nix III moved to raise it.

The motion failed, 4-3. In March, after the board raised the values of other high-end homes, it revisited Fumo's mansion. Member Alan K. Silberstein changed his vote, and Fumo's market value was raised by $703,000.

Voting with Fumo both times were two close associates: Harvey Levin, a real estate appraiser who had done work for Fumo and his nonprofit, Citizens' Alliance for Better Neighborhoods, and Joseph Russo, who served as the nonprofit's president.

Neither attended the hearing yesterday. Russo said he had a surgical procedure, and Levin told colleagues that he had a doctor's appointment.

James Dintino, who also had voted against raising the value in the earlier votes, this time joined his colleagues in voting for the higher value, sources said.

The board must notify Fumo of its formal decision in 10 days. He then has 30 days to file an appeal in Philadelphia Common Pleas Court.

Contact staff writer Joseph Tanfani at 215-854-2684 or jtanfani@phillynews.com.