LOUISVILLE — Half or more of the 1,096 homes destroyed in the 2021 Marshall Fire are under reconstruction or already reoccupied, and some property owners are seeking to find the silver lining of their circumstances by adopting green building solutions.

They’re being helped by companies willing to discount their services or products to help the numerous property owners who found that their home insurance policies fell far short of covering replacement costs.

Among them is Alpen High Performance Products Inc., a Louisville window manufacturer that itself was narrowly spared from the Dec. 30 wind-whipped inferno that wiped out large segments of Superior and Louisville.

To date, Alpen has placed its high performance windows in 30 rebuilt or under construction homes in the fire zone at discounts totalling about $100,000, according to Craig Maierhofer, vice president of business development for the company. It’s also the only U.S. manufacturer of windows to be used in so-called passive homes that are under construction. Passive homes [see related story] are those that are 90% more efficient than a traditional home being built under existing building codes and can see interior temperature variations of only a few degrees season to season.

To achieve that status means construction using different materials and highly efficient windows.

“We have the windows with the lowest U-value in the United States,” said Maierhofer. 

U-value is the inverse of R-value, he explained. U-value is used with windows; it measures how quickly heat will transfer. The lower the number, the better. A low U-value also means a higher R-value, which is the holy grail for homebuilders seeking to be energy efficient.

A window on the Alpen production floor last week awaiting shipping had a U-value of 0.14, which equates to an R-value of 7.14. A typical three-pane window manufactured by others might have an R-value of 2.5. Alpen windows are manufactured over a range from R-5 to R-11.

Maierhofer said Alpen achieves its highly efficient ratings by a combination of the glass configurations it uses, the gases it uses between the panes, and the frame construction.

Alpen, founded in 1981, has a storied history. All 6,514 windows in the Empire State Building, for example, were fitted with Alpen windows in 2011. 

It was the first to be certified for passive home construction, he said. It has a few competitors but almost none domestically. A couple of European manufacturers have begun to market in the U.S.

Maierhofer said that the U.S. Department of Energy challenged the company to devise a three-panel window using thin glass. The result was the development of glass that is one millimeter thick. The window uses outer panes that are of 1/8th or 1/16th inch in thickness — manufactured in Loveland by Cardinal Glass Industries Inc. The glass in the middle is so thin that it flexes almost like plexiglass. Multiple thin panes can be installed for four or five pane windows.

Krypton gas is inserted once the edges are sealed to a level of between 92-94% of capacity. A proprietary “lung” or balloon is attached to the fill valve to equalize pressure as a window is transported from the 5,338-foot altitude of Louisville over the mountains or to sea level locations. Like a bag of potato chips bought on the Front Range and hauled to a ski resort, expansion occurs and without a relief valve a window will lose efficiency, he said.

Alpen’s staff of 146 employees manufactures between 90 and 120 windows per day that are distributed to 46 states. 

In addition to its thin glass construction, it has developed a patented technology that it calls WinSert. It’s an insert, almost like a storm window, that can be inserted into the existing window frame to increase efficiency without a full window replacement. It’s often used in large structures where replacement of all the windows would be impractical.

Maierhofer said the company plans expansion — it will keep its headquarters in Louisville but likely add another production facility along the East Coast where it is experiencing customer growth. “Aggressive energy codes” are driving some of that, he said.

Its efforts to capitalize on the passive home market reflects its interest in staying abreast of green technology. “It’s a small but massively growing space,” he said.