by Jack Ewing

FRANKFURT — Glasbau Hahn could easily be mistaken for one of the auto repair shops or plumbing supply outlets that characterize a former factory district a few miles from Frankfurt’s banking quarter.

Yet the family-owned glassmaker, with 140 employees, not counting a Hahn grandchild running around the front office, typifies the small, highly focused companies that may propel Germany back to growth.

The paradox is that such companies are also making life difficult for Germany’s European Union partners.

Glasbau Hahn is a miniature multinational company, generating more than 60 percent of its sales abroad and dominating its narrow but lucrative niche: the global market for museum display cases. Even King Tut’s mummy lies in a climate-controlled vitrine made in Glasbau Hahn’s workshop, which sits next to a railyard and across the street from a Fiat showroom.

As Glasbau Hahn and thousands of other small German exporters rebound from a dreadful 2009, they give the European Union a much-needed shot of growth. Unfortunately, some of their success comes at the expense of countries like Greece, Spain and Portugal.

The so-called peripheral countries have incurred crushing debts in part because they bought too many Mercedes cars and other imports from Germany and elsewhere, without producing enough of their own export goods. In fact, goods from Greece, Spain and Portugal were often no longer competitive because in the last decade those countries had let wages rise faster than productivity and had become too expensive.

At the same time Germany, a country of savers, exported more than it consumed, profiting from its spendthrift neighbors but not reciprocating by buying equal amounts of imports.

“These bubbles that have been growing on the periphery are a mirror image of that surplus that Germany produces,” said Erik Berglöf, chief economist at the European Bank for Reconstruction and Development in London. “It’s roughly akin to China and the U.S. It gives rise to many tensions.”

Germany’s trade surplus is by far the largest in Europe, reaching 135.8 billion euros ($184.9 billion) in 2009, according to Eurostat, the European Union’s statistics office. Germany’s surplus was more than triple that of the Netherlands, which was in second place.

The countries with the biggest trade deficits are also the ones with biggest economic problems: Britain, Spain, Greece and Portugal. Only France, which also ranks among the top five trade-deficit countries, has a relatively healthy economy.

Glasbau Hahn helps explain why Germany is so competitive. The company and those similar to it are sometimes called hidden champions. They learned long ago to compensate for slow domestic growth by expanding overseas. And to offset the high cost of labor in Germany, they concentrate on premium products that customers are willing to pay more for.

“We’re never the cheapest,” said Till Hahn, elder statesman of the family that has owned and managed the company since 1836.

But Mr. Hahn, a cheerful 72-year-old dressed in corduroys and an argyle sweater, points out that price is secondary to a museum curator entrusted with a Gutenberg Bible. “In 20 years, no one will ask what the vitrine cost,” he said “What matters is the preservation of the object.”

Glasbau Hahn applied an engineer’s mentality to a seemingly mundane object. Its vitrines have elaborate dust-protection and climate control systems. The glass panels slide open with the touch of a remote control.

Glasbau Hahn’s display cases are found in top museums, including the British Museum in London, the Rijksmuseum in Amsterdam and the State Hermitage Museum in St. Petersburg, Russia.

The company has built cases to hold copies of the Declaration of Independence at the New York Public Library and the mummy of King Tutankhamen in Luxor, Egypt, where a custom-made glass enclosure from Frankfurt preserves the boy monarch in a nitrogen atmosphere.

Glasbau Hahn’s expertise and reputation has helped it beat competitors in Italy and Belgium, just as other German companies have beat their European rivals.

The problem that policy makers are wrestling with is how to correct the economic imbalances that German competitiveness creates.

It hardly makes sense for Germany to export less. “How do you tell German companies they shouldn’t be winners?”

asked Tommaso Padoa-Schioppa, a former member of the European Central Bank’s executive board.

One solution might be for Germany to cut taxes to stimulate consumption. But a tax break now would only worsen a budget deficit

that is already in violation of euro-zone rules.

Ultimately, the onus is on the weaker countries to address the mismatch between pay and productivity. “This gap has to be closed just as Germany did in the past decade,” said Mr. Padoa-Schioppa, who is now chairman for Europe at a consulting firm, the Promontory Financial Group.

In fact, German workers were once the ones known for being too expensive and inflexible. But for years, unions have accepted modest wage increases, and they agreed to measures that help companies address fluctuations in demand without resorting to mass firing.

For example, Glasbau Hahn — which is not unionized — managed to avoid any layoffs last year by deploying so-called work-time accounts, a widely used tool. Employees bank overtime hours during busy periods. When business is slow, they work less but draw on the accounts to keep receiving the same pay.

Employers also have come to value Germany’s political stability and the skills of its workers, even when they are more costly. In the coming week, Sun Chemical, a maker of specialty inks for food packaging based in Parsippany, N.J., will inaugurate a new plant in Frankfurt employing 120 people.

“You can get cheaper labor in other countries,” said Rudi Lenz, chief executive of Sun Chemical. “But we need trained and experienced people, and you find them in Germany.”

Like many other German companies, Glasbau Hahn suffered through a severe slump in exports last year. But this year, orders have taken off again, including a contract to supply display cases for a renovation of the New York Metropolitan Museum of Art’s Islamic galleries.

“Last year we had too little work, this year we have too much,” Mr. Hahn said.

There are tentative signs that Glasbau Hahn represents a wider upswing in German trade. Though exports plunged 18 percent last year, they increased 3 percent in the fourth quarter from the third quarter, government data released Wednesday indicated.

A visit to Mr. Hahn’s memorabilia-filled office, in fact, serves as a reminder that it would be wrong to bet against German companies. They have seen worse.

A watercolor on one wall depicts what little was left of Glasbau Hahn’s workshops at the end of World War II. Mr. Hahn retrieves from a cabinet samples of souvenir glass coasters that the company sold to American G.I.’s after the war — anything to keep the business going.