HVAC

Related Measures

• Nonresidential Laboratory Airflow

  This proposal includes requirements for nighttime set-back controls (or other demand-based controls); alignment with ASHRAE 90.1, section 6.5.7.3 allowing an alternate compliance pathway using exhaust air heat recovery; and a variable fan control on the exhaust fan for reducing fan speeds.

• Nonresidential Cooling Towers

  This proposal includes measures that improve the energy and water efficiency of cooling towers: Investigate code modifications to 1) increase the existing prescriptive efficiency requirements for axial fan, open-circuit cooling towers, and 2) ensure blowdown controls are working properly.

• Nonresidential HVAC Controls

  Title 24 includes aggressive HVAC controls requirements, but they have not been realized often enough in practice. Rather than placing the burden on designers and plans examiners, ASHRAE Guideline 36 moves the process “upstream” to the manufacturer level where the controls are programmed into equipment and savings are automatically realized.

• Compartmentalization and Balanced Ventilation / Indoor Air Quality (IAQ)

  This proposed measure would add a mandatory measure for all multifamily units (except garden-style units) to lower the compartmentalization tested leakage value and use supply-only or balanced ventilation as a whole dwelling unit strategy—in other words, use of exhaust-only ventilation could not be used for whole dwelling unit ventilation.

• Nonresidential HVAC Space Heating

  This proposal will seek to improve the energy efficiency of space heating systems in nonresidential buildings. All-electric hydronic designs are becoming more popular as more buildings choose to forego natural gas for space heating. However, as more of these systems are installed, attention must be paid to their efficiency, which this proposal will do.

• Nonresidential Commercial Kitchens UPDATE: DKV is no longer being considered for the 2025 code cycle.

  This proposal covers two measures related to commercial kitchens: demand control kitchen ventilation (DCKV), and all-electric readiness requirements.

• Single Family Buried Ducts and Cathedral Ceilings – Buried Ducts is no longer being considered for the 2025 Code Cycle

  This measure proposes new prescriptive requirements in certain climate zones for higher levels of attic insulation and for ducts in the attic to be fully buried. A simplified verification approach is proposed along with updates to the value of duct burial in the compliance software. The mandatory requirement for R-4 roof deck insulation would also be exempted if ducts are buried. Additionally, this measure proposes to add a new alternative prescriptive compliance path for cathedral ceilings.

• Residential HVAC Performance

  This code change proposal includes a number of measures designed to improve the performance of Heating Ventilation and Air Conditioning (HVAC) systems in new and existing Single Family and some Multifamily residences. Most of the measures are designed to improve the performance of Heat Pumps (HPs), although in some cases the measures are applicable to other types of HVAC systems as well.

• Multifamily Restructuring

  The multifamily restructuring CASE Report will propose changes to envelope and HVAC requirements that differ under 2022 Title 24, Part 6 between multifamily buildings up to three habitable stories and multifamily buildings four or more habitable stories.