Click on [ Example in Survey ] to see a house that has used one, or more, of these sustainable techniques. Please note, this example may be only one of the houses that have used a specific T&Pbrowse the All Houses in Survey page to find more.
|Windows are a major consideration when building any house, but especially a sustainable house. They will significantly contribute, or diminish the comfort and energy efficiency of the house. Setting aesthetic design aside, the use of too many windows can cause overheating in summer, or too much cooling in winter. This is a function of their placement, and their insulating parameters.
The insulating value is stated as "u" (1/R value)the lower the "u" number the better. Most insulated glass is double-pane, but triple-pane is also available. The gas separating the two panes can be dry air (which is 80% nitrogen), argon, or kryptoneach gas has a different insulating value, and cost.
"Low-e coatings" are another factor to consider in choosing windows. Essentially, a low-e coating for cold climates, like the Methow, allow the sun's infrared rays ("heat") to pass through the window into the house, but not to pass back out, thus increasing a window's u-value (for warm climates, low-e coatings help keep infrared rays out of the house). The "solar heat gain coefficient" (SHGC) is a measure of a low-e window's efficiency. The SHGC can range from 01, the higher the number the more efficient the window is in retaining heat in the house (in warm climates a low SHGC is preferred). Coatings reduce the transparency a bit, but the increase in insulating value is usually worth the trade-off. There are many different types of low-e coatingsplease consult your designer/architect or window vendor for advice.
Another consideration for windows is to design their placement in the house to facilitate the movement of air. One example would be a low opened window pulling in cool air and a high open window or tower expelling hot air, utilizing the chimney effect.