The MetLife Building in Midtown is getting an energy-efficient, LED-powered sign to replace its iconic marker, whose 18-foot-tall letters have long glowed with 10,000 linear feet of energy-hogging neon.

The new, environmentally conscious lettering and structures will be installed later this summer at a cost of nearly $350,000, according to permits filed with the city buildings department. MetLife declined to discuss the cost.

In October, the insurance giant dumped its longtime logo and spokesdog Snoopy and launched what it calls “Navigating life together” along with its new global designs.

The building, which straddles Park Avenue between East 44th and 45th Streets, is no longer owned by MetLife, but it recently reestablished its headquarters in the tower that adjoins and overlooks Grand Central Terminal.

“The update of the signage reflects who MetLife is today, as we transform to be a more modern, consumer-facing and purposeful company,” said Metlife senior vice president Howard Pyle.

Some diehard New Yorkers still call the 1963-era building, then the world’s largest by square-feet, “the Pan Am Building” for the now defunct globe-trotting airline whose own letters graced the top along with 25-foot high globe logos on either side.

The Sky Club provided dining and a rooftop waiting area for helicopters until one flipped over while landing on the helipad in May 1977 and killed five people.

MetLife bought the building in 1981 and when Pan Am moved out and then ceased operations in 1992, MetLife put up its own letters, to the chagrin of many City dwellers.

The building was sold for a then-record $1.51 billion in 2005 to Tishman Speyer Properties which is partners with West coast billionaire, Donald Bren. In 2015, MetLife increased its occupancy with a new lease covering 550,000 square feet and said it would consolidate at the headquarters tower.

Work also just began on the east façade of the 3.1 million-square-foot behemoth to replace Metlife’s former snowflake logo that’s made of four “M”s with its new, green-and-blue, single “M.” Later this summer, the logo on the west facade also will be replaced.