- Title 24, Part 6 regulates energy use in buildings, and it reaches existing buildings when HVAC equipment, controls, or envelope components are altered or replaced.
- Benchmarking and disclosure programs for larger buildings have been part of California policy discussions; whether they apply to you depends on size and current rules, so confirm.
- Utility efficiency programs are offered by Southern California Edison, Southern California Gas, San Diego Gas and Electric, and LADWP, but offerings change; confirm current terms before committing to equipment.
- Many of the cheapest efficiency gains are controls and maintenance fixes: schedules, setpoints, economizers, sensors, dirty coils, and leaking valves.
- Electrification is a policy and market direction, but its practical fit depends on building electrical capacity, equipment type, and current local rules.
The big picture for existing buildings
Energy efficiency in commercial buildings involves four parts: what the code requires when you alter something, what policy may require you to report, what incentives may help fund improvements, and what you can simply operate better. They overlap but should be handled separately. Mixing them up is how owners end up paying for a retrofit that a recalibrated sensor would have solved, or skipping an incentive because they replaced equipment before applying.
Title 24 basics for existing buildings
Title 24, Part 6 is California's Building Energy Efficiency Standards. It is revised on a multi-year cycle, so the requirements you meet depend on the edition in effect when the permit is issued. For existing buildings, what matters is usually the scope of the alteration.
| Project type | What commonly comes into play |
|---|---|
| Replacing a rooftop unit or split system | Efficiency and control requirements for the new equipment; economizer and fault detection where applicable; acceptance testing documentation |
| Replacing ductwork | Duct sealing, insulation, and possibly testing |
| Adding or replacing controls | Programmable schedules, setback, and lockout requirements |
| Lighting changes | Separate lighting provisions; often coordinated with the same permit |
| Tenant improvement | Mechanical, lighting, and envelope provisions for the altered space; see the tenant improvement HVAC guide |
Acceptance testing means a person certified to perform it verifies that controls and systems actually work as specified, which is an area where installed equipment sometimes fails to match the paperwork. Our Title 24, permits, and HVAC replacement guide covers the permit-side process, and the commercial RTU replacement page shows how it fits a replacement project.
Benchmarking and disclosure concepts
Benchmarking means measuring a building's energy use, typically using a standard tool, and comparing it against similar buildings. California has had statewide requirements for larger commercial buildings to report energy use under certain circumstances, and some cities and utilities have their own programs or policies in various stages. The threshold sizes, reporting deadlines, and consequences have changed over time and may continue to.
- Know your square footage and ownership structure. Applicability often turns on building size and whether tenants are separately metered.
- Gather whole-building energy data. Utility account access and meter structure determine how easily you can report.
- Check with the local utility and the state energy commission for the current program rules. Do not rely on a summary from years ago, including this one.
- Treat the data as useful anyway. A year of data reveals buildings that use far more than peers, and those are the places to look first.
Utility programs: what to expect
Electric and gas utilities in California offer efficiency programs for business customers. Which utility serves a site depends on its location: Southern California Edison and Southern California Gas Company across much of the region, San Diego Gas and Electric in San Diego County and part of southern Orange County, and the Los Angeles Department of Water and Power in the City of Los Angeles. Programs are typically funded through ratepayer mechanisms and administered under state oversight.
Common program types include rebates for specific equipment, custom incentives for engineered projects, controls and monitoring-based programs, and technical assistance such as energy audits. Eligibility rules, equipment lists, and funding availability change frequently, so confirm current offerings with the utility before purchasing equipment.
Many programs require pre-approval or application before equipment is purchased or installed, and some require that work be done by licensed contractors and documented in specific ways. If you plan to replace equipment this year, ask about program requirements before signing a purchase order. We are glad to work with the documentation requirements on a bid project or retrofit, and we do not promise any particular incentive amount.
Controls and maintenance as efficiency measures
The most reliable energy savings in many buildings come from operating the existing system correctly. This does not need a capital project, only attention.
- Schedules. Confirm that equipment runs only when the building is occupied, with sensible warm-up and cool-down periods. Holidays and tenant changes often leave schedules stale.
- Setpoints and setbacks. Check that setpoints are sensible and that unoccupied setbacks work.
- Economizers. Verify damper operation and sensor accuracy; a stuck damper wastes energy without a single complaint.
- Sensors. Replace drifted temperature, humidity, and CO2 sensors that drive decisions.
- Coils and filters. Dirty coils and filters make fans and compressors work harder.
- Refrigerant charge and leaks. An under-charged system runs longer and cools less.
- Simultaneous heating and cooling. Look for zones where reheat or competing equipment fights each other.
- Water-side checks. Boilers, chillers, pumps, and valves also drift; leaking valves can cause simultaneous heating and cooling at scale.
A maintenance program with trended readings catches these. Our building controls and automation service addresses the control side, and the diagnostics guide explains how we find causes rather than swapping parts.
Electrification context
California policy has been moving toward electric space and water heating in new construction and, over time, in existing buildings, partly through energy code provisions that favor heat pumps and partly through air-quality rules that restrict some gas appliances. The details differ by jurisdiction and change often.
For an existing commercial building, practical questions come first: is there electrical capacity at the service and panel for added load, what does the equipment cost to operate on local rates, how will heat pumps perform at the site's design conditions, and does the building have space for the new equipment? Heat pump rooftop units, VRF systems, and heat pump water heaters are all real options in the right building, and there are also sites where gas equipment remains the sensible choice. See the VRF and split systems service and water heater guide. Confirm current local rules before specifying.
A sensible order of operations
- Start with operations: fix schedules, sensors, and maintenance gaps.
- Gather a year of utility data and look for outliers.
- Identify end-of-life equipment and plan replacement with the current code and utility programs in mind.
- Ask the utility about incentives before purchasing.
- Bring in an engineer for larger or more complex changes, including electrification studies.
- Document every change so improvements can be verified and reported.
Frequently asked questions
Does Title 24 apply to old buildings?
It applies to alterations, additions, and new construction. If you replace or add equipment, the current standards often apply to that portion of the work. The specifics depend on the project's scope.
Do I have to benchmark my building?
It depends on the building's size, location, and the rules currently in effect. Check with the state and local authorities and your utility for current applicability.
Can I get a utility rebate for HVAC replacement?
Often there are programs, but they change. Eligibility, equipment lists, and funding availability vary, and many require approval before purchase. Confirm current offerings with your utility.
What is the cheapest way to cut energy use?
Usually fixing operations: schedules, setpoints, economizers, sensors, and maintenance issues. These often cost much less than equipment replacement.
Should I switch to all-electric equipment now?
It depends on your building's electrical capacity, equipment age, local rules, and operating costs. A site-specific assessment is more reliable than a general rule.
Have a site this applies to?
Davinci Mechanical is the commercial and union division of Scottish Tom's Heating & Air. Send us the equipment list or the problem and we'll tell you what we'd check first.