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Controlled Environment Horticulture

Measure Description

The Statewide CASE Team proposes to evaluate indoor horticulture measures for inclusion in the 2022 update cycle of Title 24, Part 6, Building Energy Efficiency Standards. The proposed measures aim to save energy and water, while maintaining product quality and production volume for crops grown in non-stacked and stacked indoor farms. The Statewide CASE Team will consider the plant growth requirements for the following crops in the evaluation of the proposed measures: cannabis, microgreens, vegetable transplants, basil (representing herbs category), lettuce (representing leafy greens category), tomatoes (representing vine plants category), and roses.  

Controlled environment horticulture is best categorized as a covered process. The targeted sections of Title 24, Part 6 for the proposed measures include: 

  • 120.6 Mandatory Requirements for Covered Processes and 
  • 141.1 Requirements for Covered Processes in Additions, Alterations to Existing Nonresidential, High-Rise Residential, and Hotel/Motel Buildings. 

Indoor Facilities: Horticultural Lighting Minimum Efficacy

The Horticultural Lighting Minimum Efficacy measure requires a minimum photosynthetic photon efficacy (PPE) of XX micromole per Joule for luminaires used for plant growth and maintenance in indoor horticulture facilities. Appropriate minimum efficacy for horticultural lighting will be validated through manufacturer and stakeholder outreach.  

Indoor Facilities: Environmental and Irrigation Controls

The Environmental and Irrigation Controls measure proposes mandatory lighting, temperature, humidity, and irrigation controls in indoor horticulture as well as an acceptance test for those controls. Vapor pressure deficit will be evaluated as a possible control parameter. The Statewide CASE Team 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 heating, ventilation, and air conditioning (HVAC) systems will be considered. 

Indoor Facilities: Efficient Dehumidification and Reuse of Transpired Water

The Efficient Dehumidification and Reuse of Transpired Water measure proposes minimum efficiency levels for dehumidification, as well as requires reuse of transpired water in indoor horticulture facilities with more than XX square feet of canopy. The Statewide CASE Team will evaluate air-to-air heat exchange dehumidifiers, desiccant dehumidification, and heat recovery from condenser waste heat. Interactive effects of cooling and dehumidification equipment will be considered since many cooling systems provide some amount of dehumidification. The Statewide CASE Team will also consider requirements for filtering condensate from a dehumidification system prior condensate reuse. 

Indoor Facilities: Circulation Fan Minimum Performance Specifications

The Circulation Fan Minimum Performance Specifications measure sets minimum performance specifications in cubic feet per minute per Watt (cfm/W) for circulation systems in indoor horticulture. The Statewide CASE Team will refer to Bioenvironmental and Structural Systems (BESS) Laboratory ratings for agricultural circulation fans.

Greenhouses: Horticultural Lighting Minimum Efficacy

The Horticultural Lighting Minimum Efficacy measure requires a minimum photosynthetic photon efficacy (PPE) of XX micromole per Joule for luminaires used for plant growth and maintenance in greenhouses that utilize supplemental lighting for plant growth. Appropriate minimum efficacy for horticultural lighting will be validated through manufacturer and stakeholder outreach.  

Greenhouses: Envelope Requirements

Conditioned greenhouses are currently required to comply with Title 24, Part 6 general envelope and insulation requirements. The Statewide CASE Team will evaluate envelope requirements specific to greenhouses to align code requirements with industry practices. Appropriate U-value materials will be validated through manufacturer and stakeholder outreach.  

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

Provide Feedback

This measure description will be updated as research is developed to support the 2022 code cycle. For questions or suggestions, email info@title24stakeholders.com. 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.