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Community and Q&A

Window options – large picture window

user-1121392 | Posted in Energy Efficiency and Durability on

We are building a new home in the Omaha, NE area and have a number of windows on the north side of the house. We are planning to use triple-pane IGU’s from Cardinal in fiberglass frames from Inline (window units will be assembled locally).
There is one window in our plan that is too large to be made in this same manner. This window is 8′ wide and 6′ high (96×72). Also, this window is located under a covered deck so solar heat gain, etc. is really not a factor. We have found a couple of different options for this window and would like to get input from others as to which option they feel makes the most sense.

Here are the options:
1. Loewen aluminum clad (exterior) window with Douglas Fir interior with triple-pane IGU.
The wood frame will not match the fiberglass frames from Inline being used on other windows
exactly but the “profile” is a close match and we are planning to just paint the wood to match the
color of the fiberglass frames…also, this window is not located directly next to any other windows
so differences in frames may be masked a bit by this. Approx. cost is $2000.

2. Inline fiberglass frame with an double-pane IGU from Cardinal with the i81 coating on surface #4.
Frames would match other windows but we’re not sure of the thermal performance…Cardinal
touts the i81 coating as giving triple-pane performance in a double-pane window, but it’s a
relatively new product and we haven’t found much real-world information on it yet. Will this
window be “drafty” with cold, north winter winds blowing against it? Approx. cost is $1300.

3. Inline fiberglass frame with a double-pane IGU with Heat Mirror (from Southwall via Serious).
Again, frames match. Also, we’re fairly confident in the thermal performance. Biggest concern
here is the sheer size of the window and therefore the size of the heat-mirror film….basically
we’re concerned that having an 8’x6′ piece of the heat-mirror film is just asking for problems.
We don’t have any “hard” evidence supporting this but have seen others posting issues with film
failures and the issues seem to be more prevalent the larger the window. Cost for this option is
very similar to option #1, approx. $2000.

OK, there you go…which option do you think makes the most sense?

(Thanks in advance for your input!)

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  1. DRKdesign | | #1

    Dave. Seeing that the news about the heat mirrors is somewhat dicey at best, I would not recommend #3. As a designer, I would highly recommend not choosing a different window profile for one window. It;s your house and for all time you will be looking at the window and seeing that it does not match the others. This would drive be bonkers. The best choice, personally, would be #2. You still get to have that 8'x6' glazing and performance loss will be insignificant in the overall scheme of things. My 2 cents.

  2. GBA Editor
    Martin Holladay | | #2

    I imagine that you have important architectural reasons for installing a 6 foot by 8 foot fixed window, but it's important to remember that there are drawbacks to such a huge window.

    The glazing will be extremely heavy, especially if you specify triple glazing. That makes installation complicated. It also makes it very expensive and complicated to replace the glazing if it ever gets broken, cracked, or suffers a failed seal.

    There is a reason that your window supplier says that your proposed window is "too large to be made." I would strongly advise you to consider filling this open with smaller ganged fixed windows.

    Remember the cathedral builders of Europe? They made larger cathedrals every century, until some of the cathedrals collapsed. That's how they discovered the limits of their materials and construction techniques.

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