Piecing together the energy puzzle. (upgrading the lighting fixtures and energy systems at Standard Insurance Center and Standard Plaza)(includes related article)(Focus on Construction & Energy)

Energy remodel at Standard towers balances concerns of landlords, tenants

They only come out at night.

They travel with the precision and thoroughness of a well-trained squadron, moving in groups like a swarm of nocturnal bees canvassing a field of flowers. In the morning, the only signs of their deeds are brighter lighting and oil drums full of fluorescent tubes crowding the loading dock.

Eight months, 21,000 new light fixtures and several digitally controlled HVAC systems later, two of Portland's better known office towers have trimmed their kilowatt consumption. The 29-story Standard Insurance Center and its kissing cousin, the 17-story Standard Plaza, are winding up what has been the city's biggest-ever energy retrofit.

The project came about as part of a five-year general facilities upgrade to give the buildings a more up-to-date look. The Center, known for its trademark white marble fountain, was built in 1969. The smaller Plaza building is vintage 1963.

"It all started as an outgrowth of a desire to upgrade the buildings for our tenants," says Trond Ingvaldsen, second vice president of real estate for Standard Insurance Co. "We wanted to bring the look of the building up into the '90s."

The energy efficiency improvements were introduced with an eye toward holding down the operations bottom line.

"It seemed like a reasonable thing to consider as part of the process," says Ingvaldsen. "But when we started looking closely we realized there were some improvements possible that could give us real efficiencies that would improveour expense structure for the buildings."

The first step was to decide how much to spend and on what. With a bevy of long-term leases in place, any improvements would have to have a relatively short payback period. "Whatever we chose to do, we knew there would be no compensation from our tenants," he says. "That meant we needed to stick with improvements that would pay for themselves in energy Savings."

That led to setting a payback threshold. "We decided to only go after improvements that could pay off in under five years," …