Need For Automated Shades

You can reduce the size of the daylighting zone until you are below 0.18 and then see if the compliant square footage is still above 75%.

Brandon, We are assuming 1.8 is a typo and you meant 0.18. I think Todd is confused with the case where the VLTxWFR is less than 0.15. If this were the case, you could calculate the daylighting zone with this formula: [(VLT x WFR)/0.15] x FA

In your case, where your results indicate that you are possibly causing glare, there are no manipulations of the formulas that will get you there.

The prescriptive method is not meant to take qualifiers such as "the windows face north" into consideration. If you elect to use this very simplified method to qualify for the credit, your design must meet the calculation requirements in the most basic, prescriptive way.

Consider the other two options for meeting the credit, simulation or measurement, or consider a redesign that might include lowering the VLT of your windows.

Sorry about that, I usually get confused with the prescriptive path in regards to that issue. I guess my mind was thinking of the old glazing factor calculations. Brandon, Jill is correct with this one. I guess you'd also see it when you tried to reduce your zone and it was still above 0.18. You cannot just ever randomly increase your zone.

In regards to simulation programs, that depends on your experience and how much time you have to produce the simulation results. If you are just learning daylight sims and you are doing nothing more than just doing sims to document this credit, SPOT (Sensory Placement Optimization Tool) is a good one to start with. Other programs that take awhile to learn, AGI-32, Ecotect, Daysim, Radiance, IESV. If you have 3D Studio Max, it also does daylight sims and it's results are comparable to other daylight sim programs.