When house-hunting in Silicon Valley, it’s good to take note of how clear the windows are. Sometimes when a dual pane window appears wet or foggy, it’s not just a matter of the sprinklers hitting it, but instead could be a failure of the vacuum seal. If that’s the case, the window will not be as attractive as intended.
There are some window repair professionals who claim that they can de-fog windows with condensation (the common belief is that foggy windows must always be replaced). What many consumers do not know when purchasing dual pane windows is that many of them will fail, unlike the single pane windows they are replacing. (The Old House Authority site says 30% of the time, a replacement window will be replaced within 10 years. It also advises that “More heat is typically lost though your roof and un-insulated walls than through your windows. Adding just 3 and 1/2 inches of insulation in your attic can save more energy than replacing your windows.”)
Many of my home buyer clients for Los Gatos, Almaden, Cambrian and San Jose insist upon having dual pane windows in their future house or townhouse. Before assuming that any brand is OK, though, do some research to learn about the windows’ failure rate and how long the warranty on them will be. Dual pane windows look great and do save a little energy, but if you have to replace one third of them within ten years, it won’t be a bargain at all.
Further reading on insulation and windows