Deciding
on Windows
by David B. South
 David B. South, President of the Monolithic Dome Institute |
We don't want to spend a lot of time on various window construction. But we do want to help customers decide on what they wish to buy.
The least expensive window is the one which is mass produced and sold at the local lumber yard. It is generally made of aluminum and double strength glass. From there, we can add twin glass for thermal resistance. Then of course, we have various options for tinting, low E inserts, and more.
In window choosing, budget should be considered. If budget is of no consequence, some of the new windows with vinyl coverings make a lot of sense. If budget is of small consequence, then the window of choice may be the all wood window.
But even within this range we have windows with frost breaks in them. This means that there are two frames separated by insulation. The outer frame is insulated from the inner frame to hopefully hold down condensation.
At Monolithic, we learned that a type of thermal paint can be put on aluminum windows to mitigate condensation. Condensation is a direct and very real problem.
These code sizes are well known, so window manufacturers can tell if their particular windows meet that code.
Obviously custom windows cost more than standard models.
What I call round tops are popular today. They are either half round or elliptical shape and go over the top of the regular rectangular window. To avoid sticker shock, price these before construction begins. It is not unusual to find the 3050 bedroom window at a price of $80 to $100, but then learn that its companion round top costs more than $400.
Often, the feel and look of a round top can be faked by constructing the round top, but not inserting the window. Instead, a false window, made of stucco or some other material can be inserted.
Very few people come into your house, walk around and say, "I love your windows," and mean the construction of the windows. They may like the position, they may like the view, but very few examine the structure of the window. Windows should fit the needs of the owner.
Window size and placement is another extremely important consideration. Obviously, bedrooms need to meet escape codes. That means they must have 5.7 square feet of clear area when the window is open. The smallest dimension cannot be smaller than 20 inches and the lowest part of the window must be no higher than 42 inches above the floor.
If you have a view of the Teton Mountains you would want a large window. But if the view is limited to your neighbor's house, a small window will suffice. If you plan on putting drapes over the window and never opening them, then why bother with the window, especially a big one.
On the hand, if you are building a storefront and you want people to see in as they drive by, then you need great big windows.
Another reason for windows is ventilation. Windows used for ventilation should be opposite each other to allow breezes to blow through.
In general, we put windows that are too large and too numerous in our homes.They leak a lot of heat. They leak a lot of energy. They are in need of constant cleaning and are often very expensive.
Another type of window is the skylight or roof window. But again, we have to be careful not to get too big. An 18-inch skylight lets in a lot of light and a lot of heat. If we are in an area which needs serious air conditioning, we should probably go with a reflective, mirrored type skylight.
A solar tube is another alternative. It's a skylight on top with a silverized tube leading to a skylight on the bottom. In any case, we strongly recommend you consider the translucent skylight rather than the clear. The sun forms a shaft as it goes through the clear, creating one very bright spot in the house. But the translucent rescatters the light throughout the whole area. It seems to provide more light even though some is lost in the scattering.
Skylights can be horrible in cold climates, however. Internal moist air dumps condensation on the skylight which drips back into the house. We call these condensate leaks, but they are not a leak at all. They are just condensation of enough volume to give the homeowner fits. If skylights are used, condensation will most likely result at one time or another. Condensation can be gathered up either by a bucket or a bowl, or by a permanent drain. If a permanent drain is desired, it should be factored into the cost of the skylight.
Spend the time to learn about windows. Cost is not always the best indicator of quality.
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