For a building with an elevation with 70% glazing and the others with less than 40%, how would the baseline elevations be modelled? Would the façade with 70% glazing be modelled with 40% glazing in the baseline and the other exactly as they are, or would all facades be modelled with proportionally reduced glazing so that in total (for all facades) glazing is 40% (although one facace may still exceed the 40% threshold)? In other words, would the façade with 70% glazing be modelled in the baseline with 70% as well, if the total percentage of glazing for all facades does not exceed 40% (in total)?

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Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Tue, 01/12/2016 - 22:00

See Table G3.1-5 Baseline (c). You distribute the 40% window area in the baseline model using the same proportions as the proposed design.

Jean Marais

b.i.g. Bechtold DesignBuilder Expert

LEEDuser Basic Member

581 thumbs up

Wed, 01/13/2016 - 06:07

The way I like to think about it is surface for surface: - If a proposed case surface has glazing on it more than 40%, then reduce that glazing on that surface in the baseline to 40% - if a proposed case surface has glazing on it less than 40%, (this is true for both no glazing, i.e. zero or another percent like 38%), then the baseline is modeled EXACTLY the same In practice this means that the total is often a bit less than 40%.

Charalampos Giannikopoulos

Senior Sustainability Consultant

DCarbon

LEEDuser Basic Member

65 thumbs up

Wed, 01/13/2016 - 08:12

Thanks. That said, in case the total glazing (all facades) is less than 40%, no reduction is required even if one single facade may exceed 40% glazing. On the other hand, in case the total glazing (all facades) exceeds 40%, the reduction will be proportional to all facades down to 40%, which means that even a single facade with less than 40% will be reduced by the same percentage as a facade exceeding 40%. Is that correct?

Jean Marais

b.i.g. Bechtold DesignBuilder Expert

LEEDuser Basic Member

581 thumbs up

Wed, 01/13/2016 - 09:17

Looking in the Manual it says basically to reduce the m² for each and every window (above grade) by the same x% untill the total WWR of the (above grade) building is 40% or equal to the proposed case (as when the proposed case has less than 40%), whichever is smaller. 1. No baseline window may be larger than the proposed case window. It may be smaller.

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