In 2008, a Dutchman named L. Korn found himself in Toronto buying windows for a house he was building back in the Netherlands. Unavailable at the time in Europe, the quad-pane insulated glass he wanted could be ordered from a Canadian manufacturer, and Korn was ready to do business.
Korn placed an order for 193 insulated glass units — just the glass, no frames — with Eco Insulating Glass Inc. of Mississauga, Ontario in April 2009. The $40,400 order went to a warehouse in New York and from there was shipped by sea to his house in the Netherlands. Carpenters inserted the glass into frames that had been made in Guatemala and installed them.
The krypton-filled insulated glass units (IGUs) consisted of two sheets of glass and two sheets of Heat Mirror film. The high-performance windows were part of Korn’s plan to use only the best green building materials he could find in the construction of his 3,000-square-foot, €1.2 million home. He also bought one spare unit and stored it in a garage, just in case something happened to one of the windows in the house.
And by 2016, something did start to happen to the windows in his house. They began imploding.
“The first IGs imploded in 2016,” Korn said in an email. “It made a big bang. I had no idea what happened. I reported the problem to Eco Insulating Glass on 29 November 2016.”
Now, two years later, a total of nine windows have imploded. The manufacturer blames the problem on Korn’s decision to glue wood grilles on the outside faces of the glass and has voided its warranty. An engineer hired by Korn says the practice is common in Europe and that a manufacturing defect, not the grilles, is the most likely reason that the glass panels are failing.
In the meantime, Korn is left with a number of shattered windows and a €135,000 estimate to replace them.
The problem is not unknown
Insulated glass units consist of two or more panes of glass, with the sealed space between them typically filled with gas, often argon or krypton. After the units are manufactured, the outer panes of glass are susceptible to some distortion as temperature and air pressure change, says Dutch engineer Walter Frank Westgeest. The phenomenon is well known in the glass industry, but it rarely results in a problem.
“Yes, I’ve seen many glass panes that are curved by air pressure differences or other causes, but it hardly ever results in breaking,” Westgeest said in a telephone call. “If you look at buildings, you can see all kinds of curvature in the glass panes, especially with a certain ratio of length and width.”
An exasperated Korn hired Westgeest to find out what happened after an extended exchange of emails with the manufacturer got him nowhere. Westgeest, who works for the Dutch firm Bouwkans, is a building scientist who spent 10 years working solely for a glass consultancy.
In a report on Korn’s windows last year, Westgeest said that all of the IGs he inspected, except for one, appeared to be concave, with interior panes always distorted more than the exterior pane of glass. The wood window grilles that had been glued onto the glass were often detached, meaning they had pulled away from the glass and could no longer impede movement.
Westgeest said that he measured distortion with a straight ruler and a sliding gauge. The distortion ranged from 2mm to 8 mm (0.06 inch to 0.31 inch) on the inside pane, and from 1 mm to 4 mm (0.03 inch to 0.157 inch) on the outside pane. The uninstalled spare unit also showed an inward distortion: 3.8 mm (0.149 inch) on the inside pane.
Why do glass surfaces deflect?
Westgeest cites three reasons why insulated glass units become concave or convex in shape:
- The gas content inside the IG is constant, but the ambient air pressure where the window is installed varies. The IGU is convex at low ambient air pressure and concave at high ambient air pressure. He describes this as a “dynamic process whereby the IGU will eventually return to its original flat shape …” It is not, he adds, enough to break glass panes, but the effect is magnified when the unit was manufactured under air pressure conditions significantly different than where the windows are put into service.
- Sealants and spacers are designed to contain the gas inside the IGU, but the gas can still leak out. Argon and krypton have a tendency to move from an area of high concentration to an area of low concentration, and materials used for sealant barriers let some molecules go through more easily than others. Krypton and argon can get out, but larger oxygen and nitrogen molecules in the atmosphere can’t get in to replace it. Westgeest calls this a “molecular sieve.” In time, the sealed space inside the window is at a much lower pressure than ambient air pressure.
- A dessicant is placed inside the sealed space to absorb moisture, but when a dessicant with the wrong specifications is used, gases like argon, krypon and nitroten are absorbed instead. “Because these gases are the main content of these IGUs, the absorption or ‘disappearance’ leads to a lower pressure in the unit, which will lead to concave shaping of the IGU,” his report says.
Westgeest said the insulated glass industry has, in time, learned to cope with these problems and that reports of glass failure now are unusual. For example, IGUs can be subjected to big differences in air pressure when they are shipped from a low-altitude manufacturing plant to a house high in the Swiss Alps. Manufacturers counter the problem by inserting very small tubes that vent the interior of the window and let excess pressure escape. When the windows arrive at their destination, the tubes are sealed.
Westgeest believes that either a faulty dessicant or a faulty sealant is to blame for Korn’s window problems. “I can’t imagine anything else,” he said. “That’s the only thing I can really think of. It can be worsened by transport, but I don’t think that’s the primary cause.”
In the U.S. early IGU makers learned to tweak the internal pressure of the windows so they wouldn’t rupture on the trip from a manufacturing site in the Denver area (elevation of 5,000 feet) to the Houston area, one expert who didn’t want to be quoted by name told GBA. Early on, windows failed. Then manufacturers learned how to adjust. These days, failures on the scale of Korn’s experience are rare indeed.
The manufacturer blames the applied grilles
Glenn MacEachern, vice president for sales at Eco Glass, believes the problem with Korn’s windows stems from the decision to glue wood grilles to the outside of the glass, not a manufacturing defect.
That was the basis of a letter from Eco attorney Stephen Walters to Korn last year in which the company disavowed any responsibility for the breakage. Walters said the 20-year warranty on the window units excludes “glass breakage from any cause” and exempts units that have been retrofitted with “any type of solar film or tinted film or any other added covering to the original glass surface.”
“We have inspected the unit you shipped to Eco for review and note that your complaint is in respect of the breakage of the glass and that, in addition, the glass had an added covering to the original glass surface,” Walters wrote.
“As such, the products supplied are exempted from any warranty coverage. The glass breakage is excluded from coverage, and the glass was covered with a non-factory covering and excluded from coverage.”
Bottom line: “Eco has no obligation pursuant to the warranty or otherwise to replace the glass.”
In a telephone call, MacEachern said the grilles could interfere with the “pumping action” that any IGU undergoes with changes in ambient air pressure. “It’s a violation of the warranty,” he said. “A unit has to be able to change with changing environmental conditions.”
He said he suspects Eco’s warranty is no different on that point than a “vast majority” of IGU manufacturers. Moreover, Eco has not had any other complaints of this kind in the more than 30 years it’s been making IGUs with the Heat Mirror film developed by Southwall Technologies.
“If this problem were going to be across the board, we would have had a similar situation exist in production other than Mr. Korn’s,” he said. “This one example is the only one that we’re aware of … If there’s a problem with our production methodology then why is it just this one specific job? That’s it. I’ve not seen it anywhere else.”
The privately held company manufacturers IGUs, but not finished windows, for the North American market. MacEachern declined to be specific about production volume or sales.
A long string of emails goes nowhere
Korn has posted his tale of woe online, including a series of email exchanges with MacEachern, another Eco Glass executive named Jim Larkin, and officials at Eastern Chemical, which owns the Heat Mirror technology. The emails trace Korn’s repeated requests for an explanation and help, from the early days following the initial implosion in 2016 through his frustrated accusation last month that Eco Glass was refusing to take responsibility for its production errors and didn’t seem to care about damaging its reputation.
Eco at first seemed eager to help. In January 2017, MacEachern wrote that he was trying to find an engineer in Europe who could help assess the problem. He offered possible causes for the breakage — the frames around the units were too tight, or the sealant on the window edges was not sufficiently protected from UV light.
“Please rest assured that we are working diligently to address your situation,” he said in an email. In a followup email in April 2017, MacEachern told Korn that he was waiting to hear from Eco’s gas supplier as well as suppliers of polyurethane and silicone, who might also have some ideas.
“I’ve always been a proponent in assessing the root cause for failures so that we simply do not repeat the problem again for you,” MacEachern said. “I want to get to the bottom of things and correct the situation.”
But as time went on, the correspondence became less cordial.
By last month, Eastman was asking to be dropped from any further inquiries, and Eco made it clear it was at the end of its efforts to help.
“The bottom line here is that Eco Insulating Glass Inc. simply cannot be responsible for the mishandling or misuse of our product after delivery,” Larkin wrote.
Next steps uncertain
Korn, 56, said he originally found Eco through a Google search. No one in Europe was using Heat Mirror film at the time, so he piggybacked a visit to the Eco factory with a family trip. The visit went well. “It was all OK,” he said, “they’re not a big company.”
Separately, Korn had selected a Guatemalan firm at a building fair to manufacture the frames. He also visited that company before placing his order. The window frames were shipped separately to Holland where they were married up with the glass from Canada and installed in the house.
The windows were installed without incident, and it wasn’t until 2014 that someone pointed out to Korn that one of the windows seemed to have a concave shape. The following year, the first of the windows imploded, he said in a telephone call, but the window was in a room that didn’t get much use and he put the problem out of mind.
But the following year, two others went and Korn’s concerns grew. At Eco’s request, Korn removed a damaged window and sent it to the company for testing. On the advice of his engineer, he declined to send Eco the only uninstalled unit he had.
But, Korn says, he never was told what the tests revealed. Eco’s did not follow through on its initial offer to find an engineering firm in Europe to look into the problem, and the company did not comment on the results of Westgeest’s €1,200 report, he said.
In short, Korn doesn’t seem to have much leverage with Eco, and not much of a way forward without hiring a lawyer, a move he recognizes as an expensive next step. “If you start talking to a lawyer, the first thing he says is, ‘Well, send me 10,000 Euros and I’ll have a look into it.’ That’s the first thing they say,” Korn said. “… I’m looking into it but first I want to try if I could convince Eco Glass to handle this in a normal way.
“They have tried to get around it, and of course that has made me very upset and angry,” he continued. He hopes the website he has created will prompt others who have experienced the same problem to step forward, but so far none has.
“I have no idea,” he said when asked what he will do next. “I’m just waiting and hoping.”