[Equest-users] LEED Increased Ventilation Credit and Energy Modeling

[Lyle Keck]

Hi Joe,

What version of LEED are you pursuing?

For LEED 2009 (A90.1-2007 Appendix G), baseline and proposed ventilation rates should be modeled identically except when taking credit for demand controlled ventilation where it's not required by A90.1-2007.

For LEED v4 (A90.1-2010 Appendix G), if you are pursuing the 30% Increased Ventilation credit, the baseline model will have the typical A62.1 ventilation rates, and the proposed model will include the 30% increase in ventilation.  I believe this is incorporated in exception (c) of A90.1-2010 section G3.1.2.6.  LEED v4 and A90.1-2010 are recognizing the fact that increasing outdoor air volumes will have an energy impact, and thus project teams perusing LEED v4 will have to be cognizant of the IEQc2 credit and its potential impact on EAp2/EAc1.

I haven't seen an official LEED v4 interpretation of this issue yet, but I heard this was coming and the new language in A90.1-2010 Appendix G seems to support this.

Best,


LYLE KECK  LEED AP BD+C, EIT
SUSTAINABLE DESIGN CONSULTANT




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From: Joe Chappell [mailto:JoeC at designengineers.com]
Sent: Thursday, March 06, 2014 12:51 PM
To: 'equest-users at lists.onebuilding.org'
Subject: [Equest-users] LEED Increased Ventilation Credit and Energy Modeling

Good day,

I have a question regarding the LEED credit for Increased Ventilation (IEQc2).  This is the credit awarded for exceeding ventilation in all spaces by 30% beyond the ASHRAE standard 62.1 requirements.  It seems obvious that the design model ventilation rates would be those 30% higher than 62.1 requirements.  What then would the baseline model ventilation rates be?

If you strictly follow 90.1 Appendix G, you should always model baseline and proposed equivalent except for when taking credit for demand controlled ventilation.  However, it seems in this case that it could also be argued (by LEED) that you should model the ASHRAE 62.1 required ventilation rates in the baseline model, not those that are 30% higher and therefore pay the energy expense( most climates) for increased outside air.

Does anyone have any experience with LEED on this issue?  Thanks in advance.

Kind regards,
Joe Chappell

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