Title-24 Question of the Week

How do I calculate the conditioned floor area of a building?

For the purposes of Title-24 energy code compliance analysis the Conditioned Floor Area (CFA) is the total floor area (in square feet) of enclosed conditioned space on all floors of a building, as measured at the floor level of the exterior surfaces of exterior walls enclosing the conditioned space.  This term is also referred to in the Title-24 Energy Code simply as the floor area.

This is an important value for the purpose of compliance since the annual energy use is divided by this value to obtain the energy budget.  In the prescriptive packages, the maximum fenestration (glazing) area is expressed as a percentage of conditioned floor area.

CFA is calculated from the plan dimensions of the building, including the floor area of all conditioned and indirectly conditioned space on all floors.  It includes lofts, mezzanines but does not include covered walkways, open roofed-over areas, porches, pipe trenches, exterior terraces or steps, chimneys, roof overhangs or parking garages.  Unheated basements or closets for central gas forced air furnaces are not included, unless they are shown to be indirectly conditioned.

The floor area of an interior stairway is determined as the CFA beneath the stairs and the tread area of the stairs themselves.

The diagram below provides an example of how CFA is calculated (click on image to enlarge):

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New Title-24 HVAC Fan Airflow requirements.

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The new 2016 Title-24 Energy Code requires that new HVAC systems meet minimum airflow requirements and supply fan efficiencies.

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Studies have shown that a significant number of HVAC installations suffer from low airflow problems.  Typically the main culprit is undersized return air design.

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The new T-24 energy code requires that the airflow at the return be verified by an independent HERS rater to meet the minimum requirement of 350 cfm per ton of A/C capacity.  Installing HVAC contractors will need to make sure their installations will meet this minimum requirement, actually good duct design can result in up to 400 cfm per ton so the State minimum requirement of 350 cfm per ton is not overly restrictive.

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A second option, only available to systems without zoning dampers, is to size the return ducts according to the new Tables 150.0-C and D in the T-24 Efficiency Standards and then have a HERS Rater visually verify that the installed duct system meets the design criteria of those tables.  see tables below:

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Architects CF-1R Signature requirements

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The new 2016 Title-24 Energy Code requires that all CF-1R forms must be registered and signed off by the architect/designer of record.

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This process begins with the architect registering with either CalCerts or CHEERS, two of the approved HERS providers in the State.  We suggest you register with both as some of your projects will be uploaded to either provider.

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Registration with either provider is no charge to the architect

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Here is the link for architects to register with CalCerts, the form is called a “Builder Signature Form” but can be used by architects as well:

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Training video: how to register your company with CalCerts

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HERS duct tests are now mandatory statewide

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The new 2016 Title-24 Building Efficiency Standards  require mandatory HERS duct testing for all new construction and HVAC changeouts where the ducts are altered.

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In addition minimum airflow requirements must be met and tested by an independant HERS rater.

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We recommend HVAC installers become familiar with these new rules and perform their own “rough-in” duct tests prior to completion of the project to insure the ducts are not leaking before drywall installation.

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Also, remember that all gaps between the supply/return boots and the surrounding drywall must be sealed (caulking is fine) before the HERS duct test.  The HERS rater must visually verify that these gaps are sealed.  Most importantly if they are not sealed it is likely the system will fail the duct tests.

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We are state certified HERS raters, for any questions about duct testing or to schedule us for duct testing on your next project call us at (800) 700-0131

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Or email us at: mark@energycode.com


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New 2008 Title-24 Energy Standards

The new 2008 Title-24 Building Energy Standards have been formally adopted by the California Energy Commission and are slated to be enforced in April of 2009. Click below for a summary of the Residential and the Non-Residential changes.

2008 Title-24 summary

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Outdoor and site lighting

Outdoor lighting

Prior to 2005, Title-24 lighting standards only applied to indoor and outlighting associated with conditioned buildings; that is buildings that are heating or cooled. Now the Standards address lighting in unconditioned building as as well as general site illumination and specific outdoor lighting applications including parking lots, parking garages, walkways, and building facades.

Signs

For signs, the Standards contain both prescriptive and performance approaches to compliance. Sign Standards apply to both indoor and outdoor signs. The Standards require that the signs be illuminated with efficient lighting sources and use a specific maximum power expressed in watts per square footage of sign area.

Contact us for details on how we can assist you with your outdoor lighting designs.

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