One of the nation’s oldest window manufacturers is participating in a program aimed at producing the next generation of high-efficiency windows.

Mathews Brothers of Belfast, which has been producing windows in the state since 1854, agreed to be a partner in the rehabilitation of a former veterinary clinic at the old Brunswick Naval Air Station into a model of energy efficiency. It’s being done under the auspices of the Midcoast Regional Redevelopment Authority, which is charged with making the former base, now called Brunswick Landing, a hub for renewable energy and efficiency technology.

It’s a collaborative effort among Mathews Brothers, the U.S. Department of Energy, MRRA, Dow Corning, insulation manufacturer Dryvit and Cambridge-based Fraunhofer Center for Sustainable Energy Systems. The project is designed to test the efficiency of a new vacuum-insulated wall paneling system. Mathews Brothers was tapped to participate in the project to install its R5-rated windows at the clinic as part of a yearlong test of energy efficiency.

The DOE’s R5 Windows Volume Purchase Program was conceived as a means of reducing cost to buyers while providing business to manufacturers and creating a market for high-efficiency windows. R5 refers to an efficiency rating for building materials; typical windows in today’s homes average between a R2 and R3 rating.

Nearly 40 percent of energy consumption in the United States goes toward heating and cooling buildings, but 14 percent finds a way to slip out of a building’s envelope — its windows and walls — taking with it $133 billion a year in energy costs, according to the DOE.

“The stated goal of the DOE is to make all homes net zero energy consumptive by the year 2020, so they are setting up these milestones along the way. For 2012, it was the R5 window,” Maynes said.

But Maynes said the company was not content to rely on existing technology to achieve the rigorous efficiency goals of the R5 program. Enter Quanex Building Products, a longtime supplier of window framing to Mathews Brothers, which was aggressively pursuing the R5 market identified by the DOE.

Producing an efficient R5 window means balancing a number of factors, according to Maynes. An ideal window would keep heat in while letting light in. But the two attributes can often be at odds when striving for maximum efficiency.

A low rate of heat loss, measured as a U-value, means better insulation and resistance to heat flow, but it can often come at the cost of visible transparency.

“Breakthrough technology” from Quanex allowed Mathews Brothers to strike a balance between insulation and transparency, according to Maynes. The partnership with Quantex allowed Mathews Brothers to quickly produce a window that met the R5 standard and before long, the DOE came knocking.

“Coincidentally the timing worked out with the DOE refining what they were looking for with Quanex coming out with this new product specifically designed to work with this program. We saw that the anticipated cost of materials would make it a very competitive product in the marketplace,” Maynes said.

The site was chosen for many factors, including its location in a northern climate and size; at a little over 1,600 square feet, the building was the average size, age and construction of a typical New England home. Windows at the former clinic were originally located 6 feet above ground, but the retrofit included lowering the height to that of the average single-family home.

Over the next year, the building will be monitored for thermal efficiency, air infiltration and moisture performance before being turned back over to the authority of MRRA for future use.

Matt Dodge, Mainebiz staff writer, can be reached at [email protected].