Economist Marty Cantor says the average Long Island homeowner will be especially hard hit by the GOP tax overhaul.

"If you're an average, typical homeowner on Long Island, you're not going to fare well under this bill," says Cantor. 

A $10,000 cap on state and local deductions was included in the Republican tax overhaul approved by Congress Wednesday. 

Bob Cutler, of Great River, says he pays $18,000 a year in property taxes on his home. He says the $10,000 cap will hit him hard in the wallet, even when taking into account some of the overhaul's so-called offsets – like the doubling of the standard deduction.

"I did check with my accountant…and the offsets will not offset the tax loss on the property value," says Cutler. 

He is just one of many Long Islanders who could lose significant amounts of money as a result of the new tax code.

Another major concern is that the tax bill will decrease demand for homes on Long Island, and, therefore, hurt property values. 

Paul Llobel, of the Long Island Board of Realtors, does not think that will happen.

"I think our economy should stay strong on Long Island and our housing market will continue to grow," says Llobel. 

Llobel says home prices right now are very strong and he does not expect that to change.

Many economists believe the tax overhaul will boost the U.S. economy temporarily in 2018 and possibly 2019, but predict slower growth going forward as a result of higher interest rates stemming from larger government deficits.