Title 24 Trade-Offs: A Worked Example of What Can and Cannot Move
Components can be traded against each other in the performance method, such as glass against insulation or a furnace against the envelope, as long as the total stays within budget. Mandatory measures, lighting and appliance energy, and solar PV in place of efficiency cannot be traded. Multifamily buildings also fix dwelling-unit and outdoor lighting.
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What the trade is
The compliance manual describes the performance method as giving maximum flexibility to trade the energy performance of different building components against each other, comparing the proposed building with a standard design built from the prescriptive package. A house with more glass than the package allows can still comply if something else carries the difference; prescriptive compliance offers no such room, since every requirement in Table 150.1-A must be met on its own.
The floor nothing can lower
All applicable mandatory requirements must still be met even under the performance approach. The software may not check them for you, so a model can show a pass for a design that mandatory measures would still reject; see the 2025 mandatory measures guide.
Energy that is outside the trade
- Lighting and appliance energy is not eligible to be traded off.
- Solar PV cannot substitute for efficiency measures, since PV has no effect on the efficiency LSC; efficiency can reduce the PV needed, not the reverse.
- Multifamily dwelling-unit, outdoor and sign lighting are fixed in the budget and sit outside the performance approach; extra lighting power can only be traded from space conditioning, ventilation, water heating, the envelope or covered process systems.
A worked example
A 2,000 sq ft home at 25 percent glass, 5 points over the 20 percent standard-design ratio, carries a debit. A heat pump rated above the Table 150.1-A minimum and verified by an ECC-Rater can offset it, since both sit in the same efficiency LSC total. A code-minimum gas furnace in the same design usually fails, because the reference already assumes a heat pump, and a larger PV array cannot fix it either, since PV never touches that LSC total.
Credits for equipment ratings and installation quality above the minimum need a rater test; see which credits need one. The solar rule is on why solar cannot fix a failing efficiency result. For the overview of both routes, prescriptive versus performance compares the routes, and why a design does not comply lists causes. Multifamily work starts on the multi-family report page.
Common Title 24 Questions
- What is Title 24?
- Do I need a Title 24 report?
- How much does a Title 24 report cost?
- How long does a Title 24 report take?
- What is included in a Title 24 report?
- What plans do I need to upload?
Frequently Asked Questions
No. Lighting and appliance energy is not eligible for trade-offs in the performance method. Lighting must meet its own mandatory and prescriptive requirements.
No. Every applicable mandatory requirement must still be met, even though the software may not check each one automatically.
Explore Performance Calculations
- What Does Compliance Margin Mean on a Title 24 Report?
- What Is the Title 24 Energy Budget? LSC, Source Energy and the Old TDV
- Which Title 24 Performance Credits Need an ECC-Rater Test?
- Why Did My Project Fail Title 24? How to Read a Failing Result
- Efficiency LSC vs Total LSC: Why Solar Cannot Fix a Failing Efficiency Result
View all Performance Calculations guides → · Reports and Calculations · Title 24 guide