There's so much energy being wasted in the City-County Building, Downtown, that you can actually hear it.

In the catacomb-like basement and sub-basement beneath Pittsburgh's seat of government, steam pipes hiss and drip, sauna-like air whooshes into chilly chambers when doors swing open, and electrical transformers buzz like hives.

"You hear the transformer buzzing? Another signal of a leak of energy," said Richard Dennis, top sustainable design engineer with the firm CMX, hired by the city to help improve the building's efficiency. "That's just coming from an inefficient transformation process that's causing something to vibrate in there. That, in turn, is wasting energy."

As Mr. Dennis explored the 250,000-square-foot building last week, he found all manner of inefficiency. Start with 220 city-owned air conditioners (not counting the ones in Allegheny County offices in the same building) sticking out from metal-framed windows with duct-taped cracks. "Window units are, as a rule, the least efficient mechanism for cooling a space," he said.

He noted the cast iron radiators on some floors, the space heaters under many desks, the mishmash of lighting options, the uninsulated walls, the electrical switching gear installed in 1957 -- all inside an ornate and historic shell.

"If you look at the architecture on this building, and the composition of this building, it's absolutely gorgeous," he said. "This is a treasure to the city of Pittsburgh and needs to be operating and maintained as such."

Mr. Dennis' work, for which he can bill the city up to $120,000, is the first step in a project that will eventually enlist at least $3.4 million in federal funds to lower the $1.7 million-a-year bill for energy and heating in the 95-year-old building. His report on how to improve the building's energy usage is due in April, and is a big part of Mayor Luke Ravenstahl's bid to "green" city government.

The city also is developing efficiency improvement plans for 100 other buildings of the 330 it owns. The city's flagship building, though, will get the first and most attention.

"The reason we chose this building first is because it houses the most employees of any of our buildings, and it's arguably the most accessible to our citizens," said Lindsay Baxter, the city's sustainability coordinator. It's also the city's biggest energy user, and the place where improvements can reinforce one another, like better windows magnifying the effect of more efficient heaters.

"We really see it as also a case study or an example of what private building owners can do," she said. Green building is often associated with new construction, but what, she asked, could be greener than recycling an inefficient building into an efficient one?

The federal energy efficiency grant, like those distributed to Allegheny County and other governments in a nationwide stimulus program, was based on the city's population and area, and will go entirely to the flagship building. At $12 for each square foot in the nine-floor building with two basements and three half-floors, it will get the transformation started, but not finished.

The core of the heating system -- which uses steam to heat water which then flows through radiators -- may remain, but the leaky radiators might be replaced with more modern distribution systems. Mr. Dennis said he lopped $300,000 from a Washington, D.C., hotel's annual heat bill just by changing the temperature of the steam-heated water.

Other changes are easier, and could pay for themselves over a few years by shaving the city's utility bills.

"We're looking, for example, for the types of lighting that we're using, the types of fluorescent bulbs that we're using, the numbers of bulbs, where the lighting is located, is it efficiently located," said Mr. Dennis. He'll consider where timed thermostats or centralized heating and air conditioning controls, and motion sensors tied to lighting, might make an impact. "When you leave your office for two hours, is the light staying on, or is it smart enough to turn off?"

The savings can be used to pay for more improvements. The city also plans to use CMX's report to seek grants from the federal government and other sources to pay for more fixes.

Meanwhile, the city will pay Massaro Construction Management Services as much as $300,000 for less-extensive reviews of 100 other city buildings, from police stations to firehouses. "We need a long-term plan for all of our building stock," said Jim Sloss, the city's energy and utilities manager, "rather than doing spot repairs when things break."

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