DALLAS (Bloomberg) — Frontier Airlines Holdings Inc., a low-cost carrier trying to end three years of losses, will switch to lighter seats on its aircraft to reduce fuel use.The change will begin later this year, trimming as much as 1,584 pounds per plane and cutting fuel costs about $5.4 million a year, Joe Hodas, a spokesman for the Denver-based carrier, said in an interview yesterday. He said the cost probably will be $15 million to $20 million and declined to give a precise figure.

Frontier is making the switch as jet-fuel prices have risen 20 percent this year and as its fuel cost increased 22 percent to $343 million in the fiscal year ended March 31. Fuel was the largest expense as the carrier posted a $20.4 million net loss.

"We looked at the return on the investment and it does make sense overall because of the cost savings as it relates to fuel," Hodas said.

Each new three-seat set, from Wellington, Florida-based BE Aerospace Inc., weighs 36 pounds less than current seats. That cuts 1,584 pounds on each of Frontier's 48 Airbus SAS A319 aircraft and 1,368 pounds on each of its 12 A318s. The airline expects to save more than 2.2 million gallons of fuel a year.