Glazing options for Zone 3
We are trying to decide on window glazing options for our east facing windows in San Francisco. Our window manufacturer uses Cardinal glass and offered us two Low-e options.
Low-e 277 and Low-e 180.
If I understand the main difference is in the Solar Heat Gain – we like the idea of getting more warmth from the sun in the winter since we are always cool in San Francisco. Warmer times of the year (mostly in spring and fall) there at most one or two days a year that are too warm inside and a simple fan does the trick and never air condition. In the winter we generally heat in the AM during cold mornings that are often sunny.
Positive on the Low-e 180 is higher solar heat gain (SHGC .69 versus .41) and more clarity at night for our city view with a similar U-factor (.26 verus .25)
Negative is the 8% price premium for the Low-e180 (I guess it is used less and therefore more expensive, hard-coat verus soft-coat).
We aren’t so concerned about the additional cost, but wanted to make sure I am not missing something about the performance difference.
Full specs on the glass are here http://www.cardinalcorp.com/technology/reference/loe-performance-stats/
I am looking at the first two rows under 3/4″ double pane argon-filled.
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