WATERBURY — Green Mountain Coffee Roasters Inc. has reported positive first-quarter results.

The Waterbury-based company said Wednesday its net sales were $1.3 billion for a 13-week period ending Dec. 29, up from $1.158 billion for the same quarter the previous year.

“Our strong first-quarter performance underscores the connection consumers have to their Keurig brewers; the soundness of our business model; and the value inherent in our brand portfolio,” said Brian P. Kelley, GMCR’s president and CEO, in a statement.

Single-serve portion packets made up the bulk of sales, amounting to $863.7 million worth of product, a 21 percent increase from the same period the previous year. Sales of brewers and accessories totaled $377.3 million, an increase of 14 percent. Other products and royalties decreased by 12 percent to $98.1 million.

The number of brewers sold was 4.95 million, an increase of 18 percent over the prior year period, but that amount doesn’t include returns.

Kelley, a former Coca-Cola executive who started at the end of last year, said there is untapped potential for the Keurig single-serve brand in the U.S. and globally. The company has formed an international business unit.

“We are in the early days of a marked evolution in how consumers purchase, prepare and customize hot beverages in their homes,” Kelley said in the statement.