Okay, have a dormitory building renovation project that includes the following:
- Is registered on the National Register of Historic Places (1880-era), so is technically exempt from energy code requirements.
- Needs to improve over ASHRAE 90.1-2013 by 20% (per UFC 1-200-02 High Performance and Sustainable Building Requirements).
- Is pursuing LEEDv4 BD+C (ASHRAE 90.1-2010)
- Has existing HVAC system of air-cooled chiller with AHU's and VAV terminal units with reheat (gas-fired boilers). System may be replaced with new.
- Renovation will include all new lighting and electrical.
- Will include new window treatments. Opaque envelope improvements are yet unknown and may be minimal.
Curious how others would approach energy modeling for this...
- Build three models (Proposed, 90.1-10 baseline for LEED, 90.1-13 baseline for UFC) since the envelope requirements for baseline models changed in 2013?
- Attempt to comply with LEED requirements using LEED Interpretation ID#10481 and take the envelope baseline penalty?
- Something else?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
January 30, 2019 - 12:07 pm
Hard to say. Obviously 1 and 2 are the acceptable paths. I suppose it depends is the answer. It depends on what you end up doing in the project, how much savings are desired, and how much savings you would generate under the two scenarios. I suppose doing #1 is the only way to find out for sure.
Sarah Gudeman
Principal | Practice LeadBranchPattern
8 thumbs up
February 5, 2019 - 11:53 am
I'm thinking Option 1 is the way to go, since I'm a "need to know for sure" kind of person and we'll surely get this question regardless of the compliance path we take for LEED. Thanks for the feedback!
Nakita Reed
AssociateQuinn Evans
August 30, 2019 - 11:46 am
We ran into something similar on a project pursuing LEEDv4 ID+C (Core & Shell). Below is the unofficial interpretation response we received from ASHRAE and got GBCI to approve for our project:
Background:
The project involves renovation of a historic, unconditioned, uninsulated building modeled following 90.1 2010 Appendix G. Due to
project’s historic status, the existing building envelope cannot be altered on the interior or exterior, therefore the proposed exterior
walls will remain unchanged. There will be a new roof and storm windows added.
Interpretation:
If the building becomes conditioned after the retrofit, and meets definition of historic building in 4.2.1.3 Exception a, the baseline
building performance should be determined as follows:
a. Exterior walls are excluded from the scope of retrofit and remain as is, thus should be modeled based on the existing
condition in both the baseline and proposed design, following G1.3.
b. Windows and roof are not subject to G1.3 because they are included in the scope of retrofit. Table G3.1 #5 (f)
also does not apply, because existing building is unconditioned, so its envelope does not meet the definition of the
building envelope in Section 3. Thus, the baseline for the windows and roof must be modeled as for new
construction projects, following Table G3.1 #5 b – e.
If the building becomes conditioned as the result of the retrofit, and does not meet definition of historic building in 4.2.1.3 Exception
a, the entire envelope must be modeled as described in (b) above, based on the baseline requirements applicable to the new
construction projects.
Based on G1.1, Appendix G cannot be used for projects with no mechanical systems, thus is would not apply if the building remains
unconditioned after retrofit.
If you're still looking for guidance the unofficial interpretation from ASHRAE might be the way to go.