LEED new construction and major renovations

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Hi All,

I am working on a project that pretains renevations and addition for an exisitng building. The existing is about 60% of the total new designed building, and new constructed addition is about 40%.
The existing section will have an upgraded walls and roof. Windows will remain the same. The new section will comply with local codes.

For (LEED NC v1) modeling purposes, can I model the entire building as one building (existing and new addition)? and Once modeled, Do I compare energy reduction against New Building or Exisitng in LEED reference?

Any assistance is greatly appreciated!


Maurice Safatly's picture
Joined: 2011-10-02
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the existing/renovated portion gets compared to what is there now (envelope)

the new portion gets compared to ASHRAE Baseline

Jorge E. Torres Coto

Jorge Torres-Coto's picture
Joined: 2011-10-02
Reputation: 0

Dear Maurice,

For your information below is the CIR related to this, please use the
formula to calculate the target percent.

*9/14/2007 - Credit Interpretation Request*
The purpose of this CIR is to obtain confirmation of what is considered New
Buildings vs. Existing Building Renovations within Option 1 of this credit.
The project consists of a 120,000 SF existing building, which is part of and
connected to other buildings in a corporate campus. The building was
recently used for offices, which is the predominate use of the campus. There
is no central mechanical plant for the campus-each building has its own
mechanical system. The building is being converted to a large data center.
The building's exterior shell will be retained but the existing mechanical
and electrical systems, as well as all interior partitions, ceilings and
finishes, will be removed. In short, the building is being gutted. We will
be submitting this credit under Option 1: Whole Building Energy Simulation.
The mechanical engineer is confident that the building will save at least 7%
energy costs but not sure it will achieve 14%. Since we are required to
achieve 2 points in this credit to achieve certification, we wish to be
certain that the project will be considered Existing Building Renovation for
the purpose of awarding points for energy savings.
*10/24/2007 - Ruling*
Because the existing building shell is preserved, this project can apply for
EAc1 using the Existing Building Renovations energy cost savings thresholds.
Please note that if there are portions of the project that will be
new construction, then use the equation provided in the LEED-NC v2.1 CIR
Ruling dated 9/5/2001 (and revised on 9/21/06) to determine the appropriate
point-thresholds. The equation follows below: To calculate the optimization
point table for a project that has both existing and new construction, use
the following formula for each line of the table:
*target percent = (existing SF / total SF) * (existing percent) + (new SF /
total SF) * (new percent)*


Gurneet Singh

Gurneet Monga's picture
Joined: 2011-10-02
Reputation: 0