Simplified Method Glass Conductance Entry

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Hi all,

I'd like to be able to enter my total glazing U values in one place for
simplicity. I set my frame widths to zero and defined my window glass
type in "simplified" where I entered my total window U value in the
"Glass Conductance" field. When I check my LV-D report it shows my
windows having a lower U value than what I entered. I understand there
are some variables at play here that are likely the cause (air film
resistance and windspeed of rating (summer vs winter as shown in the
topic help). I don't understand what is going on here.


Can someone shed some light on why my LV-D window U values don't match
my "Glass Conductance" value in these circumstances?

And, how would you recommend I enter my windows if I have the overall U
value already from product data?




Riley Beise, EIT, LEED GA

Riley Beise's picture
Joined: 2011-09-30
Reputation: 0

Use the formula below to convert Glazing U-value to Conductance.

Conductance = 1/((1/Glazing U)-0.2)

This formula is from the DOE-2 Reference manual.

Best regards,


Gaurav Mehta, LEED? AP BD+C

Mehta, Gaurav's picture
Joined: 2011-09-30
Reputation: 0


If the over all U value and SC reported at the end of the LV-D report for
each exposure match yours, I wouldn't worry about it. When you are looking
at each window you are probably seeing some sort of adjustment for area.


cmg750's picture
Joined: 2010-10-05
Reputation: 0