Windows to the Past: How Craftsmen Are Restoring Beauty and Performance to Historic Architecture

Architects used to have to make compromises when specifying for historic windows and doors, but with today’s materials and glazing technologies, traditional-style products now look like the old and function like the new, making them the perfect choice for projects.

For decades, the companies profiled below have been setting the bar for benchmark products.

A premier primary source for window restoration, BlackBerry Window and Door Systems has worked on more than 80 federal historic tax credit projects over the last 35 years.

The company, which is based in Kalamazoo, Michigan, not only acts as a subcontractor and historic consultant but also provides pre-design and pre-bid consulting and analysis of the windows, doors, and fenestration on major commercial and residential buildings.

It has completed scores of projects in Michigan. It restored the wooden windows on the Isaac Agree Downtown Synagogue, which is one of the oldest synagogues in Michigan. It created replica windows, restored steel windows and doors, and restored the original exterior wood bay doors at the award-winning Detroit Foundation Hotel, a new boutique hotel set in the first fire house in America that was outfitted with motorized equipment. At the Detroit News Parking Garage, the first for autos in the United States when it made its debut in 1924, BlackBerry restored 30,000 square feet of hot-rolled steel windows and added a bird screen. 

“We are unique in our ability to provide full window restoration for large-scale projects where hundreds of windows need to be restored beyond the typical residential application of a few dozen,” says Mike Shields, who founded BlackBerry in 1980 after working as a custom builder and remodeler who specialized in renovating old residential properties.

To facilitate the restoration projects, BlackBerry offers its complimentary Historic Window Site Review to developers, architects, and construction managers or facility managers.

During a site visit, a company staff member inspects the windows and doors from the interior and exterior sides, notes the number of windows, the number of openings, the window type, style and operation, and notes the condition, examining the joinery, glazing, sealants, hardware, surface condition, and structural integrity before recommending restoration or replication. 

With this information, BlackBerry creates detailed drawings to meet National Park Service requirements, providing a written document with an estimated budget price as well as photo documentation.

“In our current market area, the Historic Window Site Review is unique,” says Shields. BlackBerry collaborates with manufacturers and millworkers that make custom products.

“This synergy has propelled our company to a dominant position in our market sector,” says Shields.

The demand for window restoration has been increasing, he says, as the State Historic Preservation Office and the National Park Service are putting an emphasis on having existing or original windows restored rather than having them removed and replaced by new ones.

Everyone on the BlackBerry team “feels we are contributing to something important, saving our American architectural heritage,” Shields says. “New buildings can be innovative and beautiful, historic buildings can be inspiring.”

A pioneer manufacturer in the industry, Cooper Historical Windows, established in 1977, specializes in historically accurate, meticulously crafted windows engineered for optimal performance and longevity.

Cooper windows are made of Accoya wood, a stable, premium material that eliminates the traditional expansion and contraction challenges associated with conventional timber.

“Our commitment to authenticity means meticulously recreating period-specific windows that honor the original architect’s vision,” says Brian Cooper, the company’s owner. “Beyond aesthetic authenticity, our restoration windows offer advanced technical capabilities.”

The family-owned business, which has some 40 employees, maintains an inventory of period-accurate 1840s, 1880s, and 1920s 3-millimeter restoration glass and also offers 6-millimeter high-performance laminated safety glass and chemically tempered restoration glass.

The company, which has one patent and two pending, is known in the industry for developing a true divided-light window with an R-value of 23, American Architectural Manufacturers Association Certification for withstanding winds up to 180 miles per hour, complete UV filtration, and superior sound-attenuation capabilities.

Cooper Historical Windows’ consulting services include on-site evaluations that analyze each window and door to develop a comprehensive report, precise budget, and well-defined scope of work.

“Our commitment to understanding the nuanced requirements of each project ensures that we deliver tailored, high-quality solutions,” Cooper says, adding that the company also offers a professional AIA-accredited course on historic sash windows that explores preservation strategies, including restoration, replication, and hybrid approaches.

Noting that high-performance glass technology is revolutionizing historic-style windows and doors, bridging preservation with modern engineering, Cooper says that “by integrating advanced restoration glass with thermally broken steel, bronze, and stainless-steel frames, contemporary window manufacturers are achieving an optimal balance between historical authenticity and cutting-edge performance.”

Cooper and his team are passionate about preserving historic windows, which they see as living testaments to architectural craftsmanship and cultural heritage. “Our commitment goes beyond mere restoration,” he says. “We view these windows as critical bridges between past and present, carefully balancing historical integrity with modern energy efficiency.”

By applying weatherstripping, adding discrete storm windows, and repairing original glass and frames, “we breathe new life into these architectural treasures while dramatically improving their thermal performance,” he says. “We believe that sustainable preservation means honoring a building’s original design while intelligently adapting it to meet contemporary environmental standards, ensuring that these windows continue to tell their stories for generations to come.”

A leader in the preservation of the historic and architectural fabric of buildings, the pioneering Kronenberger & Sons has been in business nearly eight decades.

In addition to restoring historic windows and doors, Kronenberger & Sons makes reproduction millwork to match historic profiles.

“Many of the windows we restore are over 100 years old,” says Brian Kronenberger Jr., whose family started the company in 1946. “When restored, they will last generations and can be restored again in the future.”

The third-generation Connecticut-based company, which has worked on a number of significant buildings in the state, including the Mark Twain House, the Harriet Beecher Stowe House, and the state Capitol, recently completed the restoration of the Barnum Museum in Bridgeport, restoring the exterior and its original windows, including replicating the two monumental ones in the front and the eight circular ones on the dome.

For each project, Kronenberger & Sons provides on-site documentation, cataloging the relevant elements. Hardware, coatings, and glazing are removed from each piece, samples are taken of the profiles and a sharper knife is produced to match the profile. The windows are then produced and assembled.

“Many of our projects require us to reproduce the exact profiles of window sash as well as door moldings,” Kronenberger says, adding that the company has a large library of historic knife profiles. “We catalog the profiles based on the age and location, which allows us to reach back in time to secure the correct profile required.”

The company uses old-growth materials, including Eastern white pine and Janka, which is hard and dense. Spanish cedar, which has the same grain pattern of many old windows and is durable enough for exterior use, is used in lieu of old-growth material. TB