The increase, approved by LIPA's board of trustees, takes effect Tuesday.
LIPA president and chief executive Kevin Law said the hike was unavoidable given the record prices for natural gas and oil, which are used to generate electricity.
Crude oil prices Thursday broke a record again, passing $140 a barrel.
To help those on fixed incomes, LIPA said it will spend $10 million in reserve funds to help low-income senior citizens with their electric bills.
