Understanding CA's Residential Energy Code: An easy-to-read Summary


As of July 1st 2014, California’s newest version of the Energy Efficiency Standards Code will be in effect.  Since it’s revised every 5 years or so and aims to reduce energy consumption by ±25% each time, let’s just call this what it is:  “a big deal”.

All projects submitted to the Building Department after June 30th 2014 must comply with the updated version of this Code, including:  New Construction, Additions, Alterations, and Repairs.


Over the years, California has implemented and regularly updated these standards in order to reduce buildings' consumption of electricity and natural gas, for the benefit of the Homeowner, the Economy, and the Environment.  According to California's Energy Commission, Californians have saved “more than $74 billion in reduced electricity bills since 1977" as a result of these standards (calculated by multiplying annual cumulative savings by the average electricity rate that year).

Focus of this Article:

The focus of this particular article is to better understand the "low-rise" residential standards, although it should be noted that commercial buildings certainly play a big part of the energy demand reduction equation.  The term "low-rise" refers to:  all single-family dwellings, all duplexes, and multi-family buildings with three or fewer habitable stories.

Code Title Terminology (feel free to skip this paragraph):

In effect as of July 1st 2014 are the “2013 Title 24 California Building Energy Efficiency Standards” (the most recent update since the 2008 version that was adopted in January of 2009).  The complete "2013 Residential Compliance Manual" is more than 550 pages long, not including the Forms, and intended as a supplementary guide to the overarching and larger "2013 Title 24 California Building Energy Efficiency Standards” document.

Building Components & Assemblies:

Here’s a general overview of some of the characteristics, components, and assemblies that affect Residential Building Energy Demand, and therefore are inherently regulated in some way by this Code:

> GENERAL CHARACTERISTICS such as:  Climate; Building Orientation; Consideration for Existing Conditions of Additions, Alterations, and Repairs (through Third-Party Verification)

> BUILDING ENVELOPE such as:  Construction Assemblies; Materials; Insulation; Air Leakage & Infiltration; Thermal Mass; Passive Solar Design; Overhangs & Shading Devices; Fenestration & Glazing (size, properties, location); Glazing Properties; Roofing Material; Solar Reflectance; Emissivity; Thermal Emittance; Radiant Barrier; Air Barrier; Attic Space & Conditioning; Floor Construction; Crawl Space; Basements, Garages, & Storage Space

> MECHANICAL SYSTEM such as:  Heating & Cooling Equipment; Distribution (Ducts, Plenums, Fans);  Duct Leakage, Design Diagnostics, & 3rd Party Verification & Testing; Indoor Air Quality; Ventilation (Natural vs. Mechanical); Conditioned Floor Area; Ceiling Heights; User Controls (Thermostats & Zoning)

> DOMESTIC HOT WATER such as:  Water Heating System; Distribution (Piping); Heat Element Source; Insulation; Solar Water Heating; Swimming Pool & Spa Heating

> LIGHTING & ELECTRICAL such as:  Switching Devices & Controls (Dimmers, Vacancy Sensors, etc.); Efficacy of Fixtures; Type of Luminaire (ie, LED); Lighting by Room (Kitchen, Bathroom, Garage, Laundry, Utility); Outdoor Lighting; Solar Power

How to Comply:

If this seems complicated so far, not to worry:  Your Architect will coordinate the entire process and will consult with an energy consultant as necessary to ensure your project is designed in compliance, which will be represented on a variety of forms within the Construction Drawing package that is submitted to the local regulatory agency for plan check and permitting.  Inspections and Certifications during construction will be coordinated by your Contractor and checked off by the building inspector.

MANDATORY MEASURES:  There are two different compliance “approaches” described below, but in either case, the project must at a minimum comply with the Mandatory Measures.  This includes things like lighting control, lighting efficiency, minimum insulation levels, infiltration control, equipment efficiency, third-party verification for mechanical duct sealing and leaking, airflow and fan efficacy, and certain ventilation system requirements.

Beyond the list of (minimum) Mandatory Measures, one of the two following “approaches” is also required for compliance.

THE PRESCRIPTIVE APPROACH:  (AKA “Package A”) This approach offers a Package of pre-defined requirements for building components based on the project's location (by Climate Zones).  Generally speaking, it’s an easy-to-use checklist, but because each individual component or item on the list is required to comply with a certain minimum efficiency, there is very little design flexibility.  Consider, as an example, a non-negotiable requirement such as this:  the total allowed amount of west-facing fenestration (windows) is allowed to be no more than five percent of the project's overall conditioned floor area.  What if your property boasts a sweet west-facing view of the Pacific Ocean and you wanted a giant window-wall facing west?  [Answer:  use the Performance Approach instead!]

THE PERFORMANCE APPROACH:  This approach is admittedly more complicated, and requires certain computer software to actually model building performance to calculate and verify that the proposed design’s energy use will meet its allowed energy budget.  The budget is derived from a similar model of the exact same building if it were to theoretically comply via the prescriptive approach’s list of requirements.  The performance approach, however, factors in the type of energy used (electricity, gas, etc.) and the time at which it is used.  For example, energy at times of peak demand is valued higher than energy at times of greater supply.  Because trade-offs are available, there is much more design flexibility with this approach.  Using the same example as above, with the performance approach, you can have your giant west-facing window wall if we save energy another way, such as using super high-performance glass, or providing a large shade overhang, etc. 

Although the Performance approach may sound more complex than the Prescriptive approach, the cost for the computer modeling (as low as just a few hundred dollars) is often dwarfed by potential savings stemming from being able to make trade-offs in seeking the more cost-effective design solution.


This Energy Code update, although seemingly complicated and cumbersome, is most certainly a necessary evil.  It is California’s goal to one day require all new buildings, or renovated portions thereof, to use no more energy than they create, and this Code with its periodic updates is the mechanism through which this will be possible.

Your Architect will gladly guide and facilitate your project’s compliance, as this Code change is still only one very small piece of the much larger puzzle that is building or renovating a house.  If you have any questions or need help with your project, contact us at TrèSpace Studio anytime.


Source: http://www.energy.ca.gov/title24/

11 tips for a successful renovation


Home Remodels, Renovations, and Additions can be overwhelming and stressful, even for the savviest. TrèSpace Studio has put together some tips and reminders to ensure your project is a fun and rewarding experience.

#01  Selective Idea Editing: 

Free yourself from the pressure of incorporating every inspiring concept you’ve ever seen.   Instead, consider splurging on just one or two carefully chosen items that you absolutely adore, and design everything else in simplicity around them.  For example, a reupholstered eames chair, a funky alien light fixture, or the sleek kohler karbon sink faucet; then scale back and allow all else to become supplementary background noise.  Less really is more.  A minimalist, uncluttered approach is not only proven to provide greater calm and increased happiness, but it tends to be budget-friendly too!

#02  Accommodate Yourself:

Based on your actual daily activities, create a written bullet-point list of project objectives to share with your Architect.  Are you an avid reader?  If so, add to the list “a comfy reading spot with a footrest and good task-lighting”.  Are you a foodie who loves to cook but doesn’t like the isolation of a separate kitchen?  If so, let your Architect know "the kitchen must have a direct connection to the living room, with a good view of the TV from the kitchen island."

#03  Re-Sale Marketability:

If impacts of your renovation on the resale marketability of your home are important to you, then consider keeping the overall square footage and quality of finishes in alignment with other neighborhood houses.  Both under-improving and over-improving can negatively influence the ROI (return on investment).

#04  Recognizing Limitations:

It isn’t easier than it looks.  While those of us in the industry await the inevitable DDIY (“Don’t Do it Yourself”) reality TV show, here’s a straightforward warning: Save yourself from yourself, and hire Professionals who are knowledgeable, skilled, and know the ropes.  Most construction work is required to be permitted and designed in compliance with local building codes.  Not doing so can not only be dangerous, but could also potentially invalidate your Homeowner’s Insurance.  Working with a licensed Architect during the planning and design phases will enable you to enter the Construction phase with detailed and comprehensive drawings which will significantly reduce unforeseen change orders.  Your Architect will also assist during the bidding process, and continue to make regular observations during construction to verify the work is proceeding in compliance with the Construction Documents.

#05  Realistic Budgeting:

Be realistic about your project budget and schedule.  It is not at all uncommon that construction takes longer and costs more than expected.  Before commencing, set aside an additional 'contingency' fund ranging from 15% to 25% of your overall construction budget.  Factors within your control that tend to reduce overruns include:  detailed advanced planning, having a complete and comprehensive drawing package before beginning construction, and your own speedy decision-making.

#06  Be an Asset, not a Weak Link:

Being a distraction or nuisance to your Contractor is detrimental to your own project.  Time is money, so constant disruptions will only cause project delays that will cost you in the end.  Allow your Contractor plenty of time and space to focus on the work at hand; keep children and pets out of the way; and make arrangements to live elsewhere during construction (unless there is a single dividing point between the livable space with separate access and the construction zone, where a wall or plastic barrier can easily be erected).

#07  Formal Contracts:

Having a well-written, formal, and legally-enforceable Contract is nothing short of invaluable.  Projects can (and sadly-enough plenty do) spiral out of control without a proper Owner-Contractor Agreement, which among other things helps to establish roles of responsibility and prevent unauthorized additions to project scope and cost.  Your Architect can get you started with a standard form of agreement that you can, if desired, have reviewed and further customized by legal counsel.

#08  Documentation: 

Document and Photograph every change made that will later be concealed.  This renovation may be your end-game, but the future buyer of your house will appreciate having the extra documentation, which makes your home more marketable.

#09  Build for Performance:

It's easy to focus on Aesthetics while neglecting Performance.  "It's how you look, not how you feel."  Right?  (Wrong!).  Building Performance is critical, so investing in building envelope and fenestration upgrades, and updating your mechanical, electrical, & lighting systems can significantly impact your comfort and your electric bill.  Not only that, but lighting also impacts the way everything looks, from your paint colors to your skin tone.

#10  Back for the Future: 

Renovating your house isn’t something you do every day, so while you're at it, put thought into planning ahead for the future.  While your walls are open (ex, drywall removed on one side), add some solid “backing” to support any potential future artwork, wall-mounted furniture, shelf brackets, or handicap grab bars where you may one day need them.  Also consider installing empty conduit so that down the road, you can easily add or update Audio-Visual wiring (ie, Surround Sound, HDMI, etc.) as technology changes.

#11  Color Scheming: 

If you're not naturally gifted at color schemology, there are many online resources to help establish a compatible color palette.  TrèSpace Studio's advice:  When in doubt, default to a crisp version of White with a "splash" of (just-about-any) color.  White is clean, classy, and timeless - you can't go wrong!  Unfortunately, there are literally hundreds of 'Whites' out there, each slightly different from the next.  If you want to skip the painful search process, email us and we will divulge our favorite (Subject Line:  What's your White?).