For more than a decade, the House’s virtual backbone was one very large computer — a clunky piece of equipment the size of several refrigerators that resembles the boxy electronics of 1970s sci-fi flicks.

Today, everything held on the 13-year-old mainframe could fit on a computer smaller than a breadbox. Technicians have slowly been moving its different pieces onto smaller servers, and on Friday, they ceremoniously switched off the “dinosaur.—

Once the dwelling of every committee calendar and payroll stub, it will now probably be sold for parts.

“This architecture and this processing capability is obsolete to say the least,— said Richard Zanatta, director of facilities for House Information Resources. The mainframe, he said, ate up $700,000 annually in maintenance costs; now, its job is done on computers that need no such care.

Chief Administrative Officer Dan Beard’s decision to switch over to 21st-century electronics is not solely for the sake of reliable technology (though that certainly plays a role). It’s also part of his goal to make the House as energy-efficient as possible, which includes whittling down the chamber’s massive use of electricity.

Each year, the Capitol complex — including House and Senate buildings — runs up an $80 million utilities bill. Every computer, every light and every heater contributes to that total, and leaders in both chambers have been working to scale back where they can.

For the House, that has included the consolidation of servers and a recent renovation of the House’s computer facility in the Ford House Office Building. Today, the House uses 150,000 watts of electricity an hour to keep its computer system running. Four years ago, it used 500,000 watts.

Technicians now have room to offer more services and to accommodate the growing number of e-mails, Web hits and computer files, said Jack Nichols, HIR director of enterprise operations.

[IMGCAP(1)]“It gave us the power to enhance the services we provide to Members,— he said. “Using that new technology allows us to do the best for the American taxpayers. We’re getting the best bang for our buck.—

To further save energy and money, House officials also are encouraging Members to give up the physical servers in their offices for virtual space on a server in the Ford Building.

The difference is stark. The House once spent more than $500,000 in electricity each year for the servers and their backups; if all 441 Member offices switch to a virtual server, the cost will be less than $40,000.

Zanatta and Nichols say the up-front costs for the virtual system will pay for itself in short time. The system, including encryption capabilities and a backup, cost $3 million. But the physical servers in Member offices are replaced every three years. At $8,000 each, that’s about $3.5 million for 441 separate servers.

So far, House officials have transferred 119 servers to the virtual system, and 35 are in the process of being switched over. Each of those Members gets a hidden bonus for taking the step, Nichols said: Once the server is gone, they no longer have to use more than $20,000 of their annual office budget to pay for an outside technician to maintain it.

A staffer in the Senate Sergeant-at-Arms office said the Senate has also begun offering Members the option of a virtual server to save on energy and cost.

CAO spokesman Jeff Ventura called the effort a “cash cow— that gets little public attention for its part in the House’s greening goals. Indeed, other efforts are more apparent in staffers’ day-to-day lives or are more controversial — such as the cafeterias’ switch to biodegradable utensils and the expensive effort to change the Capitol Dome’s lighting.

But on Friday, as senior operating technician Gloria Washington turned off the circa-1996 mainframe, a small circle of her colleagues cheered and gathered around to take pictures. To them, it was a long-awaited step.

“It’s the end of an era,— Washington said.