An Overview of 2025 Energy Code Updates

Every three years California updates its building codes under Title 24. The Energy Code, Part 6, is no exception, but unique to the Energy Code, California by law must show cost effectiveness, meaning long-term operational savings will offset any upfront cost increase.  This process requires the California Energy Commission (CEC) to continually evaluate proposed energy saving measures before they become part of the new code. According to the CEC the proposed 2025 Standards are estimated to provide $4.8 billion in statewide energy cost savings.

The new 2025 Energy Code was formally adopted by the CEC in September 2024 and will take effect January 1, 2026.

Some key take-aways from the 2025 code cycle include:

•       Encourage energy efficient heat pump technology for space and water heating

•       Expand PV systems and battery storage standards

•       Improve indoor air quality by strengthening ventilation standards

•       Save water and save energy by reducing water use in homes and non-residential buildings

Libraries, which are often used as shelters, are now singled out with increased requirements for PV solar and battery energy storage systems.

And Restaurants, which are considered high energy users, have a fairly dramatic increase in the PV and battery capacity requirements under the 2025 Energy Code Standards.

Through our partnerships with Regional Energy Networks (RENs), we will be offering free online energy code update courses throughout this year and into 2026. Classes are usually one hour and cover different project types.  For 3C-REN (SLO, Santa Barbara and Ventura counties), check out their training calendar, and of course you’re welcome to connect with the free Energy Code Coach service.

We’re also providing training and energy code coach services for Inland REN (I-REN – San Bernardino and Riverside Counties), and the newly-formed Central California Rural REN (CCR-REN – Central Valley, Monterey, Inyo and more). If you have a group that would like training, reach out – we may be able to come to you!

We look forward to supporting our region in implementing the current code while preparing for the new code cycle.

How to Make HRV/ERVs Work for Your Design ... and Your Client

All homes, rather all occupants, need fresh clean outside air. California building code requires a certain amount of outside air (OA) be introduced into our homes through a steady mechanical system. The OA system(s) are governed by California’s Energy and CALGreen Codes – referenced under the Indoor Air Quality (IAQ) Ventilation section.

As new construction builds become tighter, with less air-infiltration and exfiltration, we are starting to see more of our clients choose balanced ventilation systems in order to maintain the tight building envelope. Exhaust-only ventilation, such as a continuously running bathroom fan, meets the building code default minimum required ventilation, but also pulls makeup air through cracks in the building envelope, creating unwanted air infiltration.

Balanced ventilation systems can be as simple as one exhaust fan and one supply fan operating simultaneously. But for a more energy efficient system, and potentially a simpler installation, a ducted heat recovery or energy recovery ventilation (HRV /ERV) unit can be used. These units use a bypass system to recover heat (and in the case of ERVs, moisture) and exchange it between outgoing air and incoming fresh air.

Photo: Example of a multifamily installation with easily accessible Merv 13 filter and ERV Core.

Optimizing

While these products have been on the market for over a decade, we find that their performance and client benefit can be optimized by following a few tips.

First, noise levels are generally low for ERV/HRV units, but higher fan speeds can result in “humming” or vibrations. It’s always a good idea to consider options for isolating the unit from framing and/or using a duct silencer in the design.

Second, with any HRV/ERV system it is important to let the design/construction teams and the homeowner or maintenance personnel know that the code required MERV 13 filter needs to be changed regularly. Some HRV/ERV units can be ordered with HEPA filters, meeting and exceeding the MERV 13 requirement in California.  Additionally, the interior of the unit and core will need periodic cleaning, typically done with a vacuum.

Lastly, because HRV/ERVs run continuously, it is important to let the homeowner or occupant know that in cases of very poor outdoor air quality, such as in wildlands fire, that the unit can be turned off manually, then turned back on after the air quality improves. Installers should provide an easily accessible and labeled on/off switch. Providing information near the unit on how to purchase replacement filters does wonders for actually making it happen!

Right-sizing Insulation for the Wall Cavity

In the low-hanging-fruit category of energy performance, correctly specifying and installing insulation is near the top of the list. Still, we frequently see insulation thickness that is not in alignment with the size of the wall cavity or an installation that doesn’t fit tightly.  Two big issues to address, both in the construction documents and in the field, are compression and gaps.

Compression reduces R-values

Compression can occur when the thickness of insulation required for the R-value is too large for the size of the studs. Not uncommon, the inconsistency could stem from a change of wall thickness due to plumbing conflicts, structural analysis, product availability, Title 24 requirements, etc. The impacts, though, are significant. For example, R-19 batt insulation that is 5.5” thick fully ‘lofted’ would fit in a nominal 2x6 cavity. Shove that same insulation into a 2x4 wall, and the effective R-value drops to R-12! Compression also occurs when insulation is pushed behind a pipe or conduit instead of cut around it, or when a framing bay is narrower than a nominal 16” space and the installer doesn’t cut the width of the batt.

Gaps could allow convection and condensation

Properly installed wall insulation has contact to all 6 surfaces of the stud cavity: at the header and footer, at the stud on either side, to the outside wall and to the inside wall. We put emphasis on this last surface because we often see insulation that is pushed into the cavity so much that when the sheetrock is installed there could be an inch or more gap between the insulation and the sixth surface. Be sure that batt insulation fully touches the outside wall and is fully lofted to the interior. If there is vertical airgap, convection could occur within the wall cavity, which tremendously reduces the effective R-value.

Gaps can also occur at the top of the cavity, either if insulation isn’t installed correctly or if it slumps over time. The gap at the top of a cavity is concerning as moist interior air could come into contact with a cold exterior wall, causing condensation. Condensation, of course, could lead to mold growth and health concerns.

Tips for getting the best fit

Interested in getting the best performance from your insulation? Here are few tips to consider:

·       Include a Quality Insulation Installation (QII) HERS verification as part of your project. QII applies to residential and non-residential projects, as well as new construction or alterations and covers air sealing as well as insulation.

·       Don’t just leave it to the Title 24 report - add notes to your construction drawing indicating expectations for a QII-level of installation.

·       Whether you are the owner, architect or builder, require a meeting with the insulation subcontractor prior to the start of work and communicate expectations at that time. Trouble-shoot difficult areas and discuss the company’s own quality-control process and employee training program.

·       Consider using a blown-in cellulose or similar product that fills the cavity more easily.

Looking for more information about appropriate insulation implementation? Check out the Quality Insulation Installation (QII) Handbook, developed by CalCERTS,  Questions on energy performance or Title 24 energy compliance? Reach out.

Energy Use at Home and on the Road!

With new data provided by Southern California Edison (SCE), we are noting changes in both energy source and energy cost for our homes and, importantly, on the road.  According to Edison International’s Countdown to 2045: “Although electric bills will increase, savings from reduced or eliminated fossil fuel expenses will more than offset the increase for households that adopt electrified technologies.”

A few key observations:

Less Energy Use Overall, and More Electric.

Californian are using much less total energy than in the past, with an increasing trend toward lowering use of natural gas and increasing use of electricity. This trend aligns with California’s effort to reduce carbon emissions by requiring that electricity in the grid is generated through clean alternative energy like solar and wind.

New Construction Leads the trend

Newer buildings continue to use less gas and more electricity. New homes use a third less natural gas but 50% more electricity. Onsite renewable energy is required for almost all new construction, bringing energy savings to homes with installed PVs. Use of energy storage systems such as batteries will increase due to the public interest in resiliency and in mitigating power outages, as well as building code requirements for commercial and high-rise multifamily occupancies.

Personal Transportation Makes a Difference

The adoption of electric vehicle technology is increasing more rapidly than projected. Charging a car at home increases the owner’s electric bill, but the cost increase is more than offset by their savings on gasoline.

A Bumpy Road but Results will be Long-term Savings

Reviewing the chart below, we see that today, the combined energy cost for gasoline, electricity and natural gas is over $6,600 per year for the average SCE customer.

www.edison.com/countdownto2045

As we transition to electric vehicles and home equipment, electric bills (either to the grid or to pay for onsite PVs) will increase substantially, but use of any fossil fuel will drop dramatically, so the total energy costs will fall below $3,900 per year by 2045. That reduces the “energy burden” of an average household to less than 3% of their income. The cost savings is not a straight line, however, as the costs savings of electric vehicles are not yet available to everyone, nor are the savings from renewable energy and battery storage.

In the long run, households throughout California are projected to save money, including personal transportation costs, after the transition from fossil fuels.