Question 1

What is a Title 24 report and what documents does it include?

Accepted Answer

A Title 24 report is the energy-compliance package that proves your ADU's design meets California's Building Energy Efficiency Standards (Title 24, Part 6). At its core is the registered CF1R (Certificate of Compliance) — the design-stage document your plan checker reviews alongside your architectural and MEP sheets — and it is later backed by installation and verification certificates produced during construction.What the CF1R coversThe CF1R is prepared during design and demonstrates that your ADU meets minimum requirements across every regulated system:Building envelope — insulation R-values for walls, floors, and ceilings, plus window U-factor and Solar Heat Gain Coefficient (SHGC) limits.Space conditioning (HVAC) — minimum heating and cooling efficiency, with heat pumps as the current prescriptive baseline.Water heating — a heat-pump water heater (HPWH) baseline for most new dwelling units.Lighting — high-efficacy (LED) sources and required controls.Solar PV and storage-ready provisions — with several ADU-specific exceptions.The three certificates in the Title 24 familyPeople often say "Title 24 report" to mean the CF1R, but the full compliance lifecycle uses three documents:DocumentWhat it isWho completes itCF1R — Certificate of ComplianceDesign-stage proof the plans meet the energy codeThe energy analyst, at the design stage (this is what goes in your permit set)CF2R — Certificate of InstallationConfirms equipment was installed as specifiedYour contractors, during constructionCF3R — Certificate of VerificationIndependent field verification (where required)A certified HERS rater, during/after constructionHow compliance is reachedThe CF1R records which of two paths your design uses:Prescriptive — every component individually meets a fixed minimum (R-value, U-factor, HVAC efficiency). Simple, but no trade-off flexibility.Performance — approved energy-modeling software shows your whole-building design performs as well as or better than a code-compliant baseline, letting you trade a weaker spot in one area for a stronger one elsewhere.One detail trips people up: the report must be registered with an approved data registry, not just printed from the compliance software. An unregistered PDF printout is frequently rejected at intake even when the numbers are correct.Because the CF1R fixes minimum HVAC efficiency, water-heater type, and lighting requirements, those choices flow directly into your mechanical, electrical, and plumbing sheets. The applicable code cycle and local amendments vary — confirm with your local building department. We prepare the registered CF1R as a +$240 Title 24 add-on alongside your MEP plans so the energy report and construction sheets are coordinated from the start. See Title 24 Reports or the full ADU Title 24 guide.

Question 2

Is a Title 24 report required for every ADU type in California?

Accepted Answer

In almost every case, yes — if you are building a new ADU or converting existing space into a dwelling, California's energy code (Title 24, Part 6) applies, and the permit package needs a registered CF1R. The depth of the requirements changes with the project type, but a registered report is prepared for nearly every ADU.Why an ADU triggers the requirementAn ADU is legally a dwelling unit — it has living, sleeping, cooking, and sanitation facilities — so it is treated like a residence for energy-code purposes, not like a shed or accessory structure. California's Building Energy Efficiency Standards apply to new dwelling units and to many alterations, which means the building department generally cannot issue your permit without the energy documentation in the submittal.How scope changes by ADU typeProject typeTitle 24 report?Compliance pathNew detached ADUYes — alwaysNew construction (most comprehensive)New attached ADUYesNew construction for the added conditioned areaGarage / interior conversionYesAlteration rules (typically narrower)JADU (Junior ADU)Usually yesOften alteration; scope can be lighterCosmetic remodel onlyOften noNo energy systems changed — verify locallyNew detached ADUs face the most comprehensive requirements — full envelope, HVAC, water-heating, lighting, and potential solar provisions, with HERS verification of certain systems.New attached ADUs are also new conditioned space and are treated similarly to detached units for most measures.Garage and interior conversions are generally reviewed under alteration rules, which are typically narrower — solar usually does not apply, and insulation standards are triggered mainly where assemblies are actually altered — but a CF1R is still prepared and registered.A quick self-checkAre you adding new conditioned floor area? → Report needed.Are you converting an unconditioned space such as a garage or basement into living space? → Needed, under alteration rules.Are you installing or replacing HVAC, a water heater, or substantial lighting? → Likely needed.Is the work purely cosmetic — paint, flooring, cabinetry — with no energy systems touched? → Often not needed.Think of the CF1R as the energy "passport" for your ADU: without it registered and submitted, the permit package is incomplete, and what the contractor installs later has to match what the document specifies.Because the edge cases are sensitive to your jurisdiction, the applicable code cycle and local amendments vary — confirm with your local building department; the 2022 and 2025 code cycles are the ones most ADU owners deal with today, with the 2025 code applying to permit applications submitted on or after January 1, 2026. We prepare the registered CF1R as a +$240 add-on alongside your MEP plans — see California ADU requirements.

Question 3

What California climate zone is my ADU in and why does it matter?

Accepted Answer

Your ADU's climate zone is determined by its project address — California is divided into 16 climate zones, and your jurisdiction's location maps to one of them. It matters because the climate zone drives nearly every number in your Title 24 report: insulation levels, window performance, HVAC sizing assumptions, and whether a solar PV requirement applies.Why the climate zone is the foundation of the reportCalifornia's 16 climate zones each have different temperature, humidity, and solar characteristics, so the energy code sets different minimums for each. The same ADU design that easily complies in a mild coastal zone may need more insulation or better windows in a hot inland or cold mountain zone. The climate zone affects:Envelope requirements — required insulation R-values and window U-factor / SHGC limits.HVAC assumptions — heating- vs. cooling-dominated design and equipment sizing inputs.Solar PV — the system size, where required, is typically calculated from conditioned floor area and the climate zone.Performance modeling — the baseline your design is compared against in the energy model.How to find your climate zoneConfirm the exact project address (street address, not just the city).The address determines the jurisdiction and the assigned California climate zone — your local building department and the energy software both reference the same official map.Once the zone is set, the CF1R applies the correct minimums for envelope, HVAC, water heating, lighting, and solar.Because the climate zone is keyed to the address, confirming the correct project address up front is one of the most important things you can do to keep your report accurate — an address change can change the entire energy model.What it means for your plansThe climate zone is one of the clearest reasons the Title 24 report and your MEP plans should be prepared together. The zone sets the efficiency targets in the CF1R, and your mechanical and electrical sheets then have to specify equipment that meets them. For example, a detached ADU in a hot inland zone may be modeled around tighter window SHGC limits and a heat pump sized from a Manual J load calculation reflecting the higher cooling load — details that need to be consistent across the report and the drawings.The applicable code cycle and local amendments vary — confirm with your local building department, and we'll set the CF1R to your jurisdiction's zone. We prepare the registered report as a +$240 Title 24 add-on alongside your MEP plans; see Title 24 Reports or the ADU Title 24 guide.

Question 4

What is HERS testing and when is it required?

Accepted Answer

HERS testing is independent, third-party field verification of certain energy measures by a certified HERS (Home Energy Rating System) rater. Where it is required, the rater inspects and tests the installed work and signs off on the CF3R (Certificate of Verification) — confirming that what was actually built matches what the Title 24 report assumed.How HERS fits the compliance lifecycleHERS verification is the construction-stage backstop to the design-stage CF1R. The three documents work in sequence:CF1R — the design-stage Certificate of Compliance prepared with your permit set.CF2R — the Certificate of Installation completed by your contractors as equipment goes in.CF3R — the Certificate of Verification completed by an independent HERS rater for measures that require field testing.The HERS rater is independent of the contractor on purpose, so the verification is impartial.When HERS testing is typically requiredThe exact triggers depend on your design and code cycle, but HERS verification commonly applies to measures that can only be confirmed in the field, such as:Duct leakage — when the ADU has a ducted HVAC system, duct sealing is often HERS-verified.Refrigerant charge / airflow — for certain ducted systems, depending on equipment and zone.Building envelope air leakage — where a blower-door test is required by the chosen compliance approach.Specific performance-path credits — measures the energy model relied on may need HERS confirmation.Many compact ADUs designed around a ductless mini-split heat pump avoid some duct-related HERS tests simply because there is no duct system to verify — one reason ductless systems are popular in ADU design. This is design-dependent, not a guarantee.What this means for your projectHERS testing happens after your plans are approved and the systems are installed — it is not part of preparing the report itself, and you arrange the rater (or your contractor does) during construction. What we do at the plan stage is make sure the CF1R clearly identifies which measures will require HERS verification, and that the mechanical and other sheets are designed so those measures can pass.Because the specific tests required, and any exemptions, depend on your design and jurisdiction, the applicable code cycle and local amendments vary — confirm with your local building department. We prepare the registered CF1R noting the applicable HERS measures as a +$240 Title 24 add-on alongside your MEP plans; see Title 24 Reports.

Question 5

What changed with the 2025 California Title 24 energy code for ADUs?

Accepted Answer

California revises its Building Energy Efficiency Standards on a three-year cycle, and the 2025 code took effect for permit applications submitted on or after January 1, 2026. For ADUs, the broad direction continues the state's push toward all-electric, high-efficiency building — heat pumps and heat-pump water heaters as baselines — with refinements to envelope, ventilation, and electrification-readiness provisions. Which cycle applies to your project depends on when you submit.The two cycles ADU owners deal with todayCode cycleApplies to permit applications2022 Title 24 (Part 6)Submitted before January 1, 20262025 Title 24 (Part 6)Submitted on or after January 1, 2026The submittal date generally determines the cycle, so a project permitted in late 2025 typically follows the 2022 code, while one submitted in 2026 follows the 2025 code. Confirm the cutoff handling with your jurisdiction, since some have intake-timing nuances.What the 2025 direction emphasizes for ADUsRather than inventing specific numbers, here is the practical thrust of the current code direction for new ADUs:Heat-pump baselines. Heat pumps remain the prescriptive baseline for space conditioning, and heat-pump water heaters remain the baseline for water heating in most new dwelling units.Electrification readiness. Continued emphasis on solar-ready and battery/energy-storage-ready (ESS-ready) provisions for many new units.Envelope and ventilation. Ongoing refinement of insulation, window performance, and whole-dwelling ventilation (ASHRAE 62.2) requirements.Lighting. High-efficacy LED sources and required controls remain standard.Because exact thresholds, credits, and exceptions differ between the 2022 and 2025 cycles, the safest approach is to design to the cycle that will be in force when you submit — not the one in force when you start planning.What to do about itEstimate your likely permit-submittal date — this points to the applicable code cycle.Confirm the project address so the correct climate zone is applied for that cycle.Have the CF1R prepared to the in-force cycle, with equipment and provisions matched on the MEP sheets.The applicable code cycle and local amendments vary — confirm with your local building department; many cities also adopt all-electric reach codes that go beyond the statewide minimum. We set the registered CF1R to the cycle that applies to your submittal and coordinate it with your plans as a +$240 Title 24 add-on; see Title 24 Reports or the ADU Title 24 guide.

Question 6

What is the solar PV requirement for ADUs in California?

Accepted Answer

It depends on the project. California's energy code requires solar photovoltaic (PV) systems on many new dwelling units, but ADUs benefit from several important exceptions. Many newly built detached ADUs end up not requiring their own PV system, while others do — the deciding factors are the project type, the roof, and the main home's existing solar.When solar may be requiredFor certain newly constructed detached ADUs, a PV system may be required, with the system size typically calculated from the conditioned floor area and the climate zone (California has 16 climate zones, each with different solar and energy characteristics). Where it applies, the requirement is part of the Title 24 compliance package and is documented in the CF1R.Common ADU exceptionsSeveral widely used exceptions can remove or reduce the PV requirement:Existing solar on the main home. If the primary residence already has a PV system large enough to cover the ADU's calculated requirement, a separate ADU system may not be needed.Insufficient solar access. If the roof is too shaded, obstructed, or poorly oriented to host a viable array, a reduction or exception may apply.Limited available roof area. Small ADU roofs with little usable solar zone may qualify for an exception.Conversions and certain alterations. Garage conversions and similar alteration projects generally do not trigger the new-construction solar requirement.Solar-ready and storage-ready provisionsEven when a PV system isn't required up front, plans commonly must show solar-ready conduit — a pathway and panel provisions for a future array. Many new ADUs may also be subject to battery/energy-storage-ready (ESS-ready) provisions depending on the code cycle and project type.On the electrical plans, that means showing conduit routing, reserved panel space, and any identified backup circuits. The actual PV system design and installation is handled by a solar contractor; the MEP plans provide the infrastructure and the CF1R documents the requirement or the exception relied upon.What to doConfirm whether your ADU is new detached construction or a conversion.Check whether the main home already has qualifying solar.Assess roof shading, orientation, and available area for an exception.Have the CF1R document the requirement or the specific exception.Because solar rules and exceptions are sensitive to the code cycle and local amendments, confirm the specifics with your local building department. We document the applicable solar requirement or exception in the registered CF1R, available as a +$240 Title 24 add-on alongside your MEP plans — see California ADU requirements.

Question 7

What is the difference between prescriptive and performance compliance?

Accepted Answer

Both are valid ways to prove your ADU meets Title 24, recorded in the same registered CF1R. The prescriptive path requires every regulated component to individually meet a fixed minimum, while the performance path uses energy-modeling software to show your whole-building design performs as well as or better than a code-compliant baseline — trading flexibility for a more complex analysis.Prescriptive: meet every minimum, no trade-offsOn the prescriptive path, each component must individually meet its fixed requirement — wall and ceiling R-values, window U-factor and SHGC, HVAC efficiency, water-heater type, and lighting all have to clear their own minimum. It is the simplest, most predictable route, but it offers no flexibility: if one element falls short, the design doesn't comply, even if it is generous everywhere else.Performance: model the whole buildingOn the performance path, approved energy software models the entire ADU and compares it against a code-compliant baseline building. As long as your design meets or beats that baseline overall, you can trade a weaker spot in one area for a stronger one elsewhere — for example, offsetting a larger window area with better insulation or a more efficient heat pump. This is useful when site or space constraints push you off the standard prescriptive solution.Side-by-sidePrescriptivePerformanceHow it worksEach component meets a fixed minimumWhole-building model meets/beats a baselineFlexibilityNone — no trade-offsHigh — trade strengths against weaknessesComplexitySimpler, predictableMore analysis (energy modeling)Best whenStandard ADU with conventional systemsConstraints force off-baseline choicesWhich one fits your ADUA practical rule of thumb: if your ADU uses conventional, all-electric systems — a ductless mini-split heat pump, a heat-pump water heater, LED lighting — the prescriptive path is usually the cleanest. If a design choice (an oversized window wall, a tankless or storage water heater, a space-constrained equipment location) won't meet a prescriptive minimum, the performance path lets the rest of the design carry it.Either way, the path chosen in the CF1R sets the efficiency targets your mechanical, electrical, and plumbing sheets must match — and on the performance path, the equipment the model relied on must be exactly what the plans specify, or the plan checker issues a correction. The applicable code cycle and local amendments vary — confirm with your local building department. We select and document the appropriate path in the registered CF1R as a +$240 Title 24 add-on alongside your MEP plans; see Title 24 Reports.

Question 8

Why bundle Title 24 with MEP plans?

Accepted Answer

Because the Title 24 report and your MEP plans are tightly interdependent, bundling them prevents the mismatches that are the single most common cause of energy-related plan-check corrections. We offer Title 24 as a +$240 add-on prepared alongside your MEP plans, so one team keeps the registered CF1R and the construction sheets consistent.Why coordination prevents correctionsThe CF1R sets the energy targets; the MEP plans have to deliver them. When the two are prepared by separate vendors, the equipment specified on the drawings frequently does not match the assumptions baked into the energy report. Bundling keeps them aligned across:HVAC — the CF1R establishes minimum heating/cooling efficiency, and the mechanical equipment schedule specifies equipment that meets it.Water heating — the CF1R fixes the water-heater type (often a heat-pump water heater) and efficiency, which the plumbing plans reflect.Lighting — high-efficacy LED fixtures and required controls noted in the CF1R appear on the electrical plans.Solar / storage — any PV requirement or exception, plus solar-ready and ESS-ready provisions, match between the report and the electrical sheets.When two different companies prepare these independently, the equipment on the plans frequently doesn't match the CF1R assumptions — the single most common Title 24 correction. One team preparing both keeps them consistent.What bundling gets youFewer corrections — the plan checker sees matching efficiency ratings and equipment on every sheet.Lower cost — the bundled CF1R is +$240, below the typical standalone Title 24 fee from many compliance providers.One timeline, one point of contact — no back-and-forth coordinating between separate companies, and both documents are ready for submittal at the same time.How it fits our pricingItemPriceSingle discipline (M, E, or P)from $995Two disciplinesfrom $1,195Full MEP packagefrom $1,495Title 24 report add-on+$240MEP pricing scales with ADU square footage. The standard 5-business-day turnaround is included; Priority (3 days) is +$299 and Expedited (1–2 days) is +$599. Two revisions plus city corrections are included, there is no sales tax, and we serve California only.The applicable code cycle and local amendments vary — confirm with your local building department, and we'll align the CF1R to your jurisdiction. To get started, see the Full MEP package, review pricing and the cost of ADU MEP plans, or place your order.

Question 9

What are the most common Title 24 mistakes causing plan check rejections?

Accepted Answer

Most Title 24 rejections come down to a handful of avoidable issues: the equipment on the plans doesn't match the report, the report wasn't registered, the wrong climate zone or code cycle was used, or required controls and provisions were left off the drawings. Almost all of them stem from preparing the energy report separately from the MEP plans.The most frequent rejection causesEquipment doesn't match the CF1R. The single most common correction — the HVAC efficiency, water-heater type, or lighting on the plans falls below what the energy report assumed.Unregistered report. A CF1R must be registered with an approved data registry; an unregistered PDF printout is frequently rejected at intake even when the numbers are correct.Wrong climate zone or code cycle. An incorrect project address, or using the prior code cycle after the cutoff, applies the wrong minimums.Missing lighting controls. No vacancy/occupancy sensor where one is required, or exterior fixtures without a photocontrol or motion sensor.Missing solar-ready / ESS-ready provisions. Conduit routing and reserved panel space not shown on the electrical sheets.Recessed-fixture and envelope gaps. Recessed cans not called out as airtight and IC-rated; insulation or window values inconsistent between the report and the plans.Stale report after a design change. Moving a wall, window, or the water heater changes the energy model, but the CF1R wasn't updated to match.How to avoid them — a pre-submittal checklistEquipment make/model/efficiency on the plans matches the CF1R exactly.The CF1R is registered, not just printed.Project address, climate zone, and code cycle are confirmed and correct.Required dimmers, vacancy sensors, and exterior photocontrols are noted on the electrical sheets.Solar PV requirement or exception is documented, and solar-ready/ESS-ready conduit is shown.Recessed cans are airtight/IC-rated; envelope values are consistent across documents.The floor plan is locked — no layout changes after the report is built.The thread running through nearly every rejection is a mismatch between the report and the plans. Preparing both together is the most reliable way to eliminate it.The applicable code cycle and local amendments vary — confirm with your local building department. We coordinate the registered CF1R with your mechanical, electrical, and plumbing sheets as a +$240 Title 24 add-on to head off these corrections; see how it works or place an order.

Question 10

Do I need Title 24 for a garage conversion that doesn't add new floor area?

Accepted Answer

Yes — in almost all cases. Even with no new square footage, converting a garage into living space turns previously unconditioned area into a conditioned dwelling space, and that triggers Title 24 under alteration rules. A registered CF1R is still prepared; the scope is just generally narrower than for new construction.Why a conversion still triggers Title 24A garage is unconditioned space. Turning it into living space means adding insulation, HVAC, a water heater, and lighting to a space that didn't have them — and each of those is a regulated energy system. The code applies to alterations, not just new floor area, so "no added square footage" does not exempt the project.How conversion scope differs from new constructionMeasureTypical treatment in a conversionInsulation / envelopeTriggered mainly where assemblies are actually altered (new walls, ceiling, floor)HVACNew conditioning system must meet efficiency minimums (heat pump baseline)Water heatingIf added, must meet the applicable standard (HPWH baseline)LightingHigh-efficacy LED with required controlsSolar PVGenerally does not apply — conversions typically aren't subject to the new-construction solar requirementThe biggest practical differences from a new detached ADU are that solar usually does not apply and the envelope requirements are concentrated on the assemblies you actually alter — but the report itself is still required and still must be registered.What to do for a conversionConfirm the project address (this fixes the climate zone and code cycle).Have the CF1R prepared under the alteration path for the systems you're adding or altering.Make sure the HVAC, water heater, and lighting on the plans match the report.Register the report and submit it with your permit set.A common misconception is that "no new square footage" means "no energy report." The trigger is conditioning previously unconditioned space — which a garage conversion almost always does.Because alteration edge cases (like-for-like swaps, very limited scopes) are jurisdiction-specific, the applicable code cycle and local amendments vary — confirm with your local building department. We prepare the registered CF1R under the correct alteration path as a +$240 Title 24 add-on alongside your MEP plans; see California ADU requirements or Title 24 Reports.

Title 24 Reports for ADUs

Related pages

Ready to get permit-ready MEP plans?