What changed in the 2025 Title 24 energy code.
Most write-ups give you the new number without the one it replaced. Here is each 2025 change set next to its 2022 value, with the section it comes from, and what it does to the model or the certificate.
The date on the application decides
The 2025 Energy Code took effect for permit applications filed on or after January 1, 2026, and its largest single change is that a heat pump became the prescriptive baseline for both space heating and water heating in every climate zone. If the application on your project went in before that date, none of it reaches you — the job stays on the cycle that was in force when it was filed, which is 2022 for anything filed from January 1, 2023. Health and Safety Code Section 18938.5 sets that rule: the codes in effect on the date of application submittal are the codes applied to the plans and the construction. Not the adoption date, not the issuance date, not the day the slab goes in.
Two wrinkles before you assume a job is safely on the old cycle. What counts as the application date is defined locally — HCD tells building officials the date is generally established by the local government, so ask the department how it defines it. And Section 100.0(a)2 puts renewal of an existing permit on the same footing as a new application: a renewal filed in 2026 lands on 2025 even when the original did not.
A permit still sitting in plan check
The primary sources answer that by omission rather than head-on. The California Building Standards Commission lists exactly two events that pull a project onto the newer code: an issued permit that expired because construction was abandoned or did not begin within twelve months of issuance, and a permit suspended or revoked because it was issued in error. In both cases the replacement application is judged on its own date. A plan-check correction or a resubmittal under a still-live application is not on that list. Absence from a list is not an affirmative rule and I will not state it as one, but the list is short and it comes from the agency that writes it.
The flip side: a permit issued before January 1, 2026 is not protected indefinitely. Let construction lapse past twelve months from issuance and the replacement application gets read against 2025. And the one place in statute where the size of a revision is the trigger is AB 130’s model home design provision — production housing, same jurisdiction, ten-year cap. It is not a general rule about revisions. If an energy comment lands on a 2022-cycle job, answer it under the cycle the job is on — and if the plan checker raises the question, get it in writing.
The change that drives the rest
Under Section 150.1(c)6 the space-conditioning system in the prescriptive standard design is a heat pump in all sixteen climate zones. The 2022 version set it only in Climate Zones 3, 4, 13 and 14. Water heating moved differently: a heat pump water heater was already the 2022 baseline statewide under Section 150.1(c)8, and what 2025 deleted was the exception that let those same four zones install a gas or propane tankless unit instead. That leaves a 240V heat pump water heater, a NEEA Tier 3 unit, or solar with electric backup. The CEC calls the package a move to a single fuel baseline.
Gas is not banned. It is off the prescriptive path, so it has to be traded for on the performance path under Section 150.1(b)1 — tighter envelope, better glass, more PV, something. On plenty of designs that is buildable. On some it is not, and that is cheaper to learn from a model than from a correction letter.
What did not change, despite what you may have read
Four corrections I can support from the standards text on both sides:
- PV did not get bigger. Equation 150.1-C and Table 150.1-C are identical across both cycles, and so are the 1.8 kWdc floor and the 80-contiguous-square-foot solar access roof area exception. What changed is the cap: 2022 capped required output at whatever would fit on that roof area, and 2025 makes it computable at 18 watts per square foot on steep-sloped roofs, 14 on low-sloped — a help on a shaded or small roof, an ADU included.
- Single-family electric-ready is not new. Sections 150.0(t), (u) and (v) — heat pump space heater, cooktop and clothes dryer ready — are word for word what 2022 said.
- Battery requirements narrowed. The 2022 storage-ready rule covered every single-family residence of one or two dwelling units; 2025 applies it only where the utility provides service greater than 125 amps, plus a new exception for buildings that already have one. No 2025 rule puts a battery on a house.
- Multifamily did not get a heat-pump baseline in 2025. It already had one — Section 170.2(c)3A is word for word identical in both cycles. The move this cycle was on the single-family side, not the multifamily side.
ADU solar did not change with this cycle either — that mandate dates to the 2019 code.
The number on the certificate is a different number
Under 2022 the energy budget was expressed as Energy Design Ratings built on source energy and time dependent valuation. Under 2025 it is source energy and Long-Term System Cost, split into Efficiency LSC and Total LSC — the code’s own terms. Part 1, Section 10-102 defines LSC as the CEC-projected present value of costs to California’s energy systems over a period of 30 years, and adds that it does not represent a prediction of individual utility bills. TDV is gone from the standards and EDR is no longer a compliance metric, so a 2025 CF1R does not compare line for line against a 2022 one. Applications from January 1, 2026 also need software approved for the 2025 code. On the public-domain side that is CBECC 2025, which merged single-family back in with nonresidential and multifamily — the 2022 cycle ran CBECC-Res alongside CBECC.
Reading the comparison below
A mandatory minimum and a prescriptive value are not the same thing. Walls are the clearest case: the mandatory floor in Section 150.0(c) tightened from U-0.102 to U-0.095 on 2×4 framing and from U-0.071 to U-0.069 on 2×6, and the R-value shortcut moved from R-13 and R-20 to R-15 and R-21, now stated for 16 inches on center — other spacing has to be shown by U-factor. But the prescriptive framed wall value in Table 150.1-A did not move at all: U-0.048 in every climate zone except 6 and 7, in both cycles. The wall change bites on projects sitting at the mandatory floor, not on prescriptive packages already past it.
Windows moved on both sides at once. The mandatory limit in Section 150.0(q) went from U-0.45, taken per product or as an area-weighted average, to a single weighted average of U-0.40. The prescriptive maximum in Table 150.1-A went from U-0.30 in every climate zone to U-0.27 in Climate Zones 1 through 5, 11 through 14 and 16, with the rest holding at U-0.30. Most values are climate-zone specific like that, so a row that reads as a tightening may be no change at your address; the climate zone page has yours.
A few rows are not model inputs at all. The ventilation-accessibility rule in Section 150.0(o)1Civ is something an architect draws, and the refrigerant-charge rows put an ECC-Rater on jobs that did not need one before. Heat pumps now need charge verification in all sixteen climate zones, where 2022 asked for it only in Climate Zones 2 and 8 through 15 — so a heat pump change-out in Climate Zone 1, 3, 4, 5, 6, 7 or 16 picks up a rater it did not have.
Prices
Flat fees, in writing before I start. No hourly, no bid package, no change-order games — the number on the quote is the number on the invoice.
Your first report with me
One per client, homes under 3,000 square feet. Full energy model, CF1R and CHEERS registration. It’s a test run — send one job and see how it goes.
Every model after the first
The standard rate once you’re a client — the second building, ADU plus main house, the next project that walks in. Back in 3 business days.
Over 3,000 square feet
Quoted from the plans before any work starts, same day.
24×36 plan-sheet set
Your CF1R laid out full size, matched to your drawing set. Comes back as a PDF you drop straight in.
Revisions
Two revisions included, plus questions any time. Past two I quote first, before I touch it.
Commercial / tenant improvement
Send the plans and you’ll have a flat quote back the same day. No retainer, no minimum.
One honest note
I’m not a licensed engineer or architect, and I don’t stamp drawings. On the CF1R I’m the documentation author — you stay the responsible designer. Nothing about your role on the job changes.
That’s on purpose. I’m not after your scope or your clients. I do one piece of the permit set — the piece that usually holds it up — and I do it fast.
2025 cycle questions
If yours isn’t here, see the full FAQ or call and ask.
My permit application went in before January 1, 2026. Which code applies?
The cycle that was in force on the day the application was submitted — the 2022 Energy Code for anything filed from January 1, 2023. It is the submittal date that fixes it, not when construction starts, so the job stays on that cycle all the way through. Older filings sit on the 2019 cycle, and I still run both. One thing worth checking if the filing was close to the line: HCD tells building officials that the permit application date is generally established by the local government, and points anyone asking to the building department, so ask the department how it defines it.
Does answering a plan check correction move the project onto the 2025 code?
The California Building Standards Commission lists only two events that pull a project onto a newer cycle: a permit that expired because construction was abandoned or did not begin within twelve months of issuance, and a permit suspended or revoked because it was issued in error. A correction or a resubmittal under a live application is not on that list. That is not the same as a published rule saying resubmittals are exempt, so if a plan checker raises it, get the answer from the city in writing.
Do I have to put a heat pump in on a 2025-cycle project?
Not necessarily, but space heating and water heating moved differently and it is worth separating them. For space heating, Section 150.1(c)6 now makes a heat pump the prescriptive requirement in every climate zone, where 2022 set it only in Climate Zones 3, 4, 13 and 14. For water heating, a heat pump water heater was already the 2022 prescriptive baseline statewide under Section 150.1(c)8; what 2025 deleted was the exception that let those same four zones install a gas or propane tankless unit instead. Either way gas is still buildable, but it has to be paid for on the performance path with something else — envelope, glazing, PV. Whether that works on a given design is a modeling question, and it is cheaper to answer before the drawings are finished.
Is my city adding a stricter local ordinance on top of the 2025 code?
Probably not a new one. AB 130 froze building standards affecting residential units from October 1, 2025 through June 1, 2031, in two places. Health and Safety Code Section 18941.5(c) stops a city or county from establishing more restrictive standards applicable to residential units, subject to five conditions — one of which preserves changes substantially equivalent to what that jurisdiction already had in effect on September 30, 2025, so an ordinance already on the books is a different question from a new one. Section 18930(g) does the same to the Commission and other adopting agencies, on its own separate list of conditions. Neither reaches the 2025 Energy Code itself, which the CEC adopted in September 2024 and the Building Standards Commission approved that December, effective January 1, 2026.
Why does the compliance margin on a 2025 report look different?
Because the metric changed. The 2022 budget was expressed as Energy Design Ratings built on source energy and time dependent valuation. The 2025 budget is expressed in source energy and Long-Term System Cost, split into Efficiency LSC and Total LSC. TDV is gone from the standards and EDR is no longer a compliance metric, so a 2025 number and a 2022 number are not comparable line for line. The glossary has the rest of the acronyms.
Did the 2025 cycle change anything for ADUs?
Less than you would think, and not the part people ask about — the new-construction solar mandate that covers a detached ADU dates to the 2019 cycle. What did change for a small unit: the required PV size is now capped at 18 watts per square foot of solar access roof area on a steep-sloped roof and 14 on a low-sloped one, a ductless space-conditioning system now qualifies for the exception to mandatory roof-deck insulation, and a new dwelling unit of 500 square feet or less in Climate Zone 5 may still use a 0.30 window U-factor. More on ADU compliance.
Send a job on any cycle.
2019, 2022 or 2025 — the plans go in and the CF1R comes back registered. If you are not sure which cycle a permit falls under, send it and I will tell you what I see.