Afghan National Army soldiers march during training exercise in Kabul, Afghanistan. NATO hopes to grow the Afghan National Army from about 97,000 troops to 171,600 by the end of next year. (AP Photo/Dar Yasin/AP PHOTO/DAR YASIN)

The commander of NATO’s elaborate and expensive effort to build the Afghan security forces, Lt. Gen. William B. Caldwell, was standing inside the bathroom of a police training school in this obscure eastern town, looking at the sinks. He did not like what he saw.

“Every time I walk into some place and see a porcelain sink, I cringe,” he said.

That’s because Caldwell is tasked with making the Afghan army and police capable of holding off the Taliban — but in a way the United States can afford. Growing political concern in the United States over the high cost of the American mission has made for a blunt new imperative: The Afghan security forces, which cost the United States $11.6 billion this year, need to get cheaper — fast.

To this end, out are the pedestal porcelain sinks in the bases the United States is building for the Afghan army and police; in are communal metal troughs. Out: air conditioning. In: ceiling fans. Out: brick-and-mortar barracks. In: quick-rising steel “arch-span” buildings.

“If they can’t afford it and sustain it in 2014” — the year Afghan security forces are scheduled to be in charge of their own destiny — “we don’t build it,” Caldwell said.

The scope of the U.S.-funded building boom for Afghan security forces nevertheless remains immense. Contractors are about a quarter of the way through a $11.4 billion effort to erect 10,000 buildings — about 100 bases for the Afghan army and nearly 1,000 sites for the police — though a large number of projects are expected to be completed by spring. They range from small police outposts to the $200 million National Defense University in Kabul.

This effort began in earnest just a couple of years ago, when U.S. officials made training and equipping the Afghan security forces a top priority. Soon some of the more glaring cultural differences became apparent, said Maj. Gen. Peter Fuller, the deputy commander for programs with NATO’s training command in Kabul.

Some Afghans were unaccustomed to Western-style toilets, for example, and would perch, squatting, on the rim of the seat, mimicking how they used the hole-in-the-floor style more common here. When gas was in short supply, some tried to convert the NATO-supplied propane stoves into wood-burning ones, with little success.

“What we’re trying to do is realize how would the Afghans operate if they were to go out and contract for a building,” Fuller said. “Let’s make things appropriate for Afghanistan. We call it ‘Afghan right.’ ”

Not by coincidence, these new construction standards also are cheaper. Just by eliminating most air conditioning in Afghan military and police bases, NATO officials estimate they are saving more than $100 million a year on fuel. The pared-down standards also result in simpler structures that NATO officials hope are more likely to be kept up after coalition troops depart.

“We’re teaching them something that’s a lot simpler, and certainly they understand,” said Col. Mario A. Trevino, a NATO engineer in Kabul.

Gen. Sher Mohammad Karimi, the Afghan army’s chief of staff, said he did not have a problem with the change in construction methods for military bases.

“I am pleased with what we have for the army,” he said in an interview. “I appreciate all of them. They are great facilities. They are not substandard. They are to international standard.”

The new frugality is a necessity, a message reiterated by congressional delegations that visit Afghanistan and remind U.S. soldiers and diplomats about economic problems back home. NATO’s planners have been operating under the assumption that it will cost $6 billion a year to maintain a 352,000-man army and police force in 2014. But they realize that figure, to include an Afghan army of nearly 200,000 soldiers, may not be politically sustainable, and they are looking for ways to field that force at a half or a third of the cost.

“How much is the United States going to be contributing in the out years? That’s what the big discussion is,” Fuller said.

The Obama administration has asked Congress to appropriate $12.8 billion for Afghan security forces in the coming year, but that request has not been approved.

Before he stepped down as defense secretary this summer, Robert M. Gates asked that the rest of the NATO nations essentially triple their contribution, to about $1.4 billion a year. NATO officials hope the Afghan government’s meager contribution will also increase.

“How do you get others besides us injecting cash into the system?” Fuller said of the American goal — beyond finding a way to “squeeze’’ the projected $6 billion annual cost of supporting Afghanistan’s security forces after 2012.

If necessary, there are other ways to save money, Fuller said, such as cutting salaries, limiting fuel or changing how often the security forces replace equipment and vehicles. But ultimately, U.S. and Afghan officials said, the answer might lie in a decision to field a smaller Afghan army than planned — particularly if there are further successes in combating the Taliban insurgency.

“There is just no need to keep a 200,000-man army if the insurgency level goes down,” Caldwell said.