01Key facts / TL;DR
Yes, conditioned additions typically need Energy Code documentation; the applicable pathway and scope must be established.
No, there is no separate addition price list: applicable residential reports use the conditioned-area tiers below.
It depends which new and existing areas enter the requested analysis; do not choose a modeling boundary solely to obtain a lower estimate.
Representative stock photography. Not our projects, staff or offices.
Published schedule
Flat prices for report preparation
Residential
By conditioned floor area in the confirmed report scope.
- Up to 2,000 sq ft
- $149
- 2,001 to 4,000 sq ft
- $199
- 4,001 to 6,000 sq ft
- $279
- Over 6,000 sq ft
- $279 + $50per additional started 1,000 sq ft
- Each additional dwelling unit
- +$75beyond the first
Revisions
- Plan-check correction caused by our modeling or report error
- Free
- Architectural or design revision after the report
- $75 flat
- Full remodel of the energy model or larger resubmittal
- Custom quoteintake required
Rush
+$99 residential. Next-business-day production after complete inputs are received. Not a permit-approval or unconditional 24-hour promise.
Not included
- ECC field verification (formerly called HERS testing in older documents)
- Nonresidential acceptance testing
- Registry or document registration fees
- CALGreen documentation
- Building department (AHJ) plan check and permit fees
No payment is taken online. Price and scope are confirmed with you before work begins. Full pricing page
Use the shared price estimator
Upload plans / Get a Quote02The addition question comes before the calculator
Adding conditioned area usually creates an energy-compliance task, but a building addition and an energy-model boundary are not identical descriptions. The plans should distinguish new conditioned area, retained existing rooms and altered existing components. That distinction informs what documentation is actually being prepared.
Some projects use an addition-alone approach; others need an appropriately supported existing-plus-addition analysis. The applicable rules and permit scope determine the available approach. A larger model is not automatically required because the spaces share a wall, and a smaller model is not automatically permitted because it costs less.
Start with the reviewing agency, recorded application date and proposed work. If the actual change converts unconditioned space without extending the footprint, explain that fact rather than calling the project cosmetic. The AHJ and responsible team should confirm classification and the required evidence.
Do I need Title 24 for an addition?Addition-alone versus existing-plus-addition
03How the published residential tiers apply
Use conditioned square footage included in the confirmed report scope, together with the dwelling units included in the request. The table above is the standard residential menu, not an addition-specific offer. Send enough plan information to explain the input instead of entering only whichever area produces a preferred price.
Residential requests include a $75 supplement for each dwelling unit beyond the first. A bedroom addition to one dwelling does not create another unit merely because it adds rooms. An independent dwelling proposal raises separate classification and scoping questions that should be stated clearly.
If an existing building model, prior report or a substantial redesign is involved, include it. A new addition report, an architectural revision to an issued package and rebuilding an existing model are different requests. The shared estimator is useful for the new-report menu; it cannot infer those distinctions from area.
04Illustrative example: 450 square feet with an incomplete boundary
ILLUSTRATIVE ONLY: a homeowner requests pricing for a 450-square-foot conditioned addition. The first drawing shows the new room but omits whether existing windows and HVAC are also altered. The preparer asks for the full proposed scope before describing the energy-document package.
The architect supplies the retained-versus-new plan and equipment intentions. The team then evaluates the supported addition pathway and whether existing areas belong in the analysis. The applicant uses the resulting scoped area and units with the published calculator; the project nickname does not select a special addition rate.
If the design later expands to include a substantially remodeled house, the original limited-scope estimate should not be treated as covering that rebuild. This example illustrates intake decisions, not a passing model, a permitted approach or a local threshold.
05Inputs that make an addition quote useful
Provide dimensioned existing/proposed floor plans, a clear conditioned-area schedule, elevations/sections, new assemblies and affected existing conditions. Identify window sizes and U-factor/SHGC, proposed HVAC or duct changes, water heating where relevant and any prior energy report. Label unavailable information rather than inventing it.
State the AHJ and its recorded permit-application date. For applications on or after January 1, 2026, the statewide default is the 2025 Energy Code. Confirm amendments, reapplications and older permits with the AHJ; construction start and the age of the house are not the controlling application date.
Explain the requested stage: an early option study, permit-ready documentation or a response to comments. If the architect is still comparing designs, ask for the study scope rather than assuming a final CF1R includes unlimited design iterations. A complete packet reduces avoidable clarification, not the city’s review obligations.
Prepare an intake packageAddition/remodel service scopeModeling options and boundaries
06Rush, revisions and construction-stage costs
Published residential rush is +$99 for next-business-day production after complete inputs. It does not guarantee permit approval, cover unresolved selections or control AHJ review time. Include your target date and ask for confirmation of the actual deliverable.
Corrections caused by our modeling/report error are Free; architectural/design changes are $75 flat; full model remodels/larger rebuilds need intake and a custom quote. Send the reviewed report, complete comments and marked-up revisions instead of assuming every addition change belongs to the flat revision tier.
ECC field verification/field testing, nonresidential acceptance testing, registry fees, CALGreen and AHJ plan-check/permit fees are excluded. CF1R design preparation is not installer CF2R certification or required ECC-Rater CF3R verification. Older-cycle records may use HERS language; keep the actual edition and responsibilities clear.
07Four addition-cost questions
Is an addition charged under a special addition menu?
No. Applicable residential documentation uses the same published conditioned-area tiers and extra-unit supplement. Confirm the report scope rather than treating the project name as a new price class.
Can I choose addition-alone just to reduce the quoted area?
No pricing estimate establishes a permitted modeling approach. First review the actual scope and applicable compliance pathway with the responsible team, then identify the area being documented.
What if the existing house changes after the addition report?
Provide the previous package and revised scope. Architectural changes and major model rebuilds have different revision tiers; the old limited-scope request does not automatically cover a larger redesign.
Does rush include inspection or city review?
No. Rush concerns production after complete inputs. Separate installer/verification tasks, inspections and AHJ review remain outside that production promise and the published report exclusions.
08Turn the estimate into a scoped project request
Use the published menu to budget, then send the actual plans and open questions. Sign-in protects submission and private uploads. No payment is taken online; submitting is not order acceptance, a production commitment or permit approval. Title 24 Lab is a provisional brand. This educational guide is not legal or engineering advice; the AHJ determines applicable requirements.
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