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Nonresidential Controlled Environment Horticulture

Measure descriptions are subject to change.

Measures

Lighting Efficiency

The current code requires luminaires or lamps that are used for plant growth to have a photosynthetic photon efficacy (PPE) of at least 1.9 micromoles per joule (µmol/J) for indoor grow facilities with more than 40 kW of horticultural lighting load. Luminaires or lamps used for plant growth in greenhouses with more than 40 kW of horticultural lighting load must have a PPE of at least 1.7 µmol/J. Both the indoor and greenhouse requirements can be met by double-ended high-pressure sodium (HPS) technology, a legacy product that has been in the CEH market for over a decade.

For the 2025 cycle, the Statewide CASE Team is analyzing the potential for increasing the PPE levels for both indoor and greenhouse facilities. Specifically, the Statewide CASE Team is proposing to increase the minimum PPE for luminaires and lamps used to grow plants in indoor facilities from 1.9 to an LED based efficacy, at least 2.3 µmol/J. This change would mandate the use of LEDs whereas HPS lamps can meet the existing requirements. The Statewide CASE Team will investigate the potential for requiring controls that operate indoor lighting systems based on Photosynthetic Photon Flux Density (PPFD) and Daily Light Integral (DLI).

For greenhouses, the Statewide CASE Team is looking into increasing the minimum PPE for luminaires and lamps used to grow plants from 1.7 to 1.9 µmol/J. Double-ended HPS lamps and LED luminaires would be able to meet this proposed level while ceramic metal halides would likely not.

HVAC and Dehumidification (HVAC/D) Equipment and Environmental Controls Integration

The Statewide CASE Team will explore mandatory environmental and irrigation controls in indoor horticulture facilities larger than a certain square feet threshold. The controls will specify the monitoring parameters specific to plant growth such as temperature, humidity, CO2 levels, as well as parameters specific to plant irrigation such as pressure in irrigation lines. Optimal values for environmental parameters will be determined for all crop types. The evaluation will consider simple controls such as thermostats, switches, time clocks, irrigation timers, irrigation controllers, pressure sensors for irrigation lines as well as more complex controls that use computerized equipment. Interactions of lighting and HVAC systems will be considered.

The Statewide CASE Team will explore potential CEH HVAC/D and controls integration measure options, although the following list is not exhaustive:

  • Minimizing dehumidifier recovered reheat when the space is being cooled
  • Maximizing dehumidifier recovered reheat before adding supplemental heating
  • Heat pump for primary reheat and space heating needs
  • 100% heat recovery for primary reheat after dehumidification
  • Heat recovery for chilled and hot water system
  • Closed-loop, water-cooled HVAC

Data Needs/Stakeholder Information Requests

  • The Statewide CASE Team would like to survey CEH lighting equipment dealers to understand what percent of each CEH lighting technology is sold through their businesses.
  • The Statewide CASE Team would like to survey CEH HVAC/D and controls manufacturers to understand what common types of equipment and controls configurations they are specifying.
  • What HVAC/D control and equipment strategies are considered inefficient?
  • What are typical maintenance requirements for LED grow lights?

Data may be provided anonymously. To participate or provide information, please email Kyle Booth, kbooth@energy-solution.com, directly and CC info@title24stakeholders.com.

Provide Feedback

Submit feedback and view the Energy Commission's proceedings and available proposed code language by visiting their 2025 Building Energy Efficiency Standards page.

This measure page will be updated as the 2025 code cycle progresses. For questions or suggestions, email info@title24stakeholders.com. Please include the measure name in the subject line.

Give Us Your Feedback

The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.

  • Use the form above to provide feedback on this measure.