Has anyone been able to calculate the daylighting provided by Solatube's with the prescriptive method? If I use the spreadsheet, it comes up with a crazy number of 1 solatube daylights 65 sf - which is no where near the capacity it actually provides, and would force you to over-daylight the space to get the calculations correct.
Has anyone come across this before? Thanks.
Brian Baewon Koh
CEO, former USGBC FacultyInnovative Design, Inc.
12 thumbs up
August 7, 2011 - 6:54 pm
Solar tubes are usually underestimated if you use the spreadsheet. It's much better to use the simulation method.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
890 thumbs up
August 18, 2011 - 8:40 am
Simulation is the best method to show your daylighting potential of the space. Remember, the prescriptive method is just a formula that is to be used by projects that are not going through truly integrating daylight. I can show you buildings that are properly daylighted (quality and quantity) meet the LEED requirements in simulation and actual measurements, that do not meet the requirement using the prescriptive method. Using the prescriptive method to provide daylight for those buildings would actual make it worse. The prescriptive method does not consider site, climate, or any other factors that influence daylight. I would highly recommend that projects that have implemented daylight strategies into their design use simulation.