I’m building a new house in Knoxville, TN (zone 4). This is a wet climate and often dark—enough to require artificial lighting during the daytime in our current house. My wife & I are willing to sacrifice some U value for brighter daylighting, because the resulting personal productivity warrants it (we both feel more innervated on dark days). One of the greatest pleasures in life is to see sunlight streaming in through windows, the way interiors are always photographed in those upscale magazines!
My design provides for eaves >= 3’, such that direct sunlight will not hit glass during the warmer months.
Does low-e contribute to insulation value when there is no direct sunlight (e.g. on the north side, or at night)?
At what value of VT does the window begin to look tinted?
The last time I installed new windows, I was quite surprised how tinted the “clear glass” was! But this was in L.A. and an advantage because it reduced glare. In TN I want no tint at all. But I also want an energy-efficient house, and I want to be a responsible member of a society heading quickly toward catastrophic global warming.
My research indicates spectrally selective glass will provide the best alternative. I welcome any recommendations for minimum acceptable VT value, minimum U value, and how to get there (i.e. window manufacturer recommendations).
Thanks to all: this is one of the biggest design decisions, and cost decisions as well!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part