Southwark Metal Manufacturing Co., a Philadelphia-based maker of prefabricated sheet-metal ducts and fittings, has opened a manufacturing plant in Caldwell.

The 79,500 square-foot plant sits on 15 acres at Sky Ranch Business Park. It will serve heating, ventilation and air-conditioning distributors in Utah, Idaho, Oregon, Washington, Wyoming, Nevada, and Montana.

Owner and President Bill Spiegel said in July that up to 25 jobs would be created when the plant opens, and more jobs would be added as the business expands. Most of the jobs are to perform assembly work.

“We are proud of the new Caldwell plant, as it demonstrates our dedication to providing the best quality products and the best regional service to our customers,” Spiegel said Wednesday. "Not only will the new division assist our current customers in meeting their business goals more efficiently, but it will help Southwark continue to grow with future opportunities in the area.”

Southwark has been making ducts and fittings for more than 60 years under three generations of family ownership.

The Caldwell plant is the company's sixth. Southwark also has plants in Pennsylvania, Nebraska, South Carolina, Mississippi and Indiana.