This is a rant that has been simmering for a few years.
However well intentioned, I think the whole notion of thermopane windows is misguided. When I started building houses in the mid 70’s the idea had really taken hold as people became interested in conserving energy and improving the comfort of their homes.
It was not long before the requirements for insulating glass became codified with different requirements varying with climate.
We are now more than 40 years past the time when I started building and most of the seals have failed on those windows. That is, except for the windows that were not sealed thermopane type. Many of the houses I built had Pella type windows with removable interior panels. Those windows are still performing exceptionally.
I do not belief it can ever be economically justified–over the life of the house–to install thermopane windows when you factor in the cost of replacing all that glass in less than 30 years. This becomes even truer if the windows are triple-pane or have funny gasses pumped into them or reflective coatings applied to them.
Some of the newer windows with the “Warm Edge Spacers” are known to fail in less than 15 years.
I think it is time to revisit the whole business of insulating glass windows and see if the use of removable panel type insulating glass–or even old fashioned storm type windows might have some merit–or at least be an option. Throwing money at the fruit so far off the ground may not have proved to be the wisest path–and is rotting by the time we get to it.
The amount of energy expended to create thermopane windows simply cannot be justified against how long they last. Well cared for windows should last indefinitely, whereas sealed unit, thermopane windows are a version of job security for the windows replacement industry.
I installed thermopane windows in my kitchen about 18 years ago, and this year two of the panes failed.
This is unacceptable in my opinion. The labor and materials to replace these units will easily cost more money and consume more energy than any imagined savings accrued over the 18 years. If the windows had been a removable glass panel type windows, they would have continued to keep on saving energy, eventually even paying for themselves over the life of the home—probably sooner.
I would like feedback from anyone that can make a case for sealed unit, thermopane windows.
Charles Buell, Real Estate Inspections in Seattle
