Will a bigger compliance margin lower my bill?

Usually it points toward a more efficient design, but the margin is not converted into dollars on your tariff.

Is a Title 24 report an energy audit?

No. It checks a design against the code and does not assess how the household uses energy.

Is a Title 24 Calculation a Prediction of My Energy Bill?

No. It is a comparison between your design and a reference house under fixed assumptions, scored in long-term system cost. The Energy Commission says that cost does not represent a prediction of individual utility bills. The compliance margin shows how you rank against the reference, not what you will pay.

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What the number measures

Long-term system cost is the Commission-projected present value of costs to California's energy system over 30 years. It is built from hourly factors that differ by hour, energy type and climate zone, so the same kilowatt-hour counts differently at noon than at dusk. A design can improve its score by shifting use to cheaper hours without using fewer kilowatt-hours. That is a statewide grid measure, and your utility tariff is something else.

Everything is standardized

Your design and the reference house are run with the same occupancy assumptions, prescribed weather and operating schedules, and the results are compared on standardized rates. Weather comes from the Commission's typical data for 16 climate zones, picked by ZIP code or zone, and the same data is applied to both buildings. Neither run reflects how your household lives.

The reference is not an average home

It is a baseline built from the prescriptive package for your floor area and configuration. A report that passes with a margin has shown that your design beats that baseline, not that it beats the house next door.

What lies outside the calculation

Only regulated uses are counted: space heating and cooling, ventilation, water heating, plus lighting and plug loads in the total score. The Energy Code does not regulate residential appliances or portable lighting, so a large part of household energy use never enters the model. Behavior, thermostat habits and utility rates do not either.

How to use the margin

Treat it as a ranking against the code, useful for comparing design options.
Do not size solar from it; see how solar counts.
For a bill estimate, ask your utility or use its calculators.

Statewide savings figures are on how much energy Title 24 saves, and two ratings are contrasted in Title 24 and the energy index. Steps are in how calculations are done. Our residential report is a compliance document, not an energy audit.

Common Title 24 Questions

Frequently Asked Questions

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