FARMINGDALE - Many Long Islanders who are planning to remodel their homes are scrambling to get their hands on energy-efficient appliances before many federal tax breaks expire.Contractor Cathy Karavas says her company has been overwhelmed lately with customers wanting to take advantage of a tax credit on energy-efficient windows. The federal government is offering a 30-percent tax credit of up to $1,500 to homeowners who seek to make their houses more energy-efficient. The tax credit, which expires at the end of the year, is good for insulation, energy-efficient electric heat pumps, central air conditioning, furnaces, boilers and wood-burning stoves. Experts say having a wood-burning stove can significantly reduce one's annual heating costs."This is a great way to make the most-inefficient part of your house the most-efficient part of your house," says Don Brunner, the owner of Westbury Stove and Fireplace.