This chapter addresses the requirements for heating, ventilating, and air-conditioning (HVAC) systems. The requirements are a source of information for mechanical system designers and installers, as well as energy consultants, Home Energy Rating System (HERS) Raters, and enforcement personnel.
Each section in this chapter outlines the mandatory measures and, when applicable, the prescriptive requirements or compliance options. These prescriptive requirements vary by climate zone and building type. If the building design does not achieve the minimum prescriptive requirements, consider using the performance compliance option that allows for making up the deficiencies with other HVAC or building features.
Each section of this chapter includes mandatory measures, prescriptive requirements and performance options The chapter is organized under the following sections:
Section 4.2 – Heating Equipment.
Section 4.3 – Cooling Equipment.
Section 4.4 – Air Distribution System Ducts, Plemums, and Fans.
Section 4.5 – Controls.
Section 4.6 – Indoor Air Quality and Mechanical Ventilation.
Section 4.7 – Alternative Systems.
Section 4.8 – Refrigerant Charge.
Section 4.9 – Compliance and Enforcement.
Chapter 9 covers the heating and cooling requirements for additions to existing dwellings and for alterations to existing heating and cooling systems.
The following is an overview of the new HVAC measures for the 2019 Building Energy Efficiency Standards (Energy Standards), including new compliance options that provide greater flexibility in complying with the Energy Standards when using the performance method.
4.1.2.1 Mandatory Features and Devices - §150.0
1. Fan efficacy requirements are 0.45 watts/cubic feet per minute (CFM) or less for gas furnace air-handling units or 0.58 watts/CFM or less for air-handling units that are not gas furnaces. This requirement applies to single zone and zonally controlled forced air systems (§150.0(m)13B and 13C).
2. Small-duct, high-velocity forced-air systems must meet a fan efficacy of 0.62 Watts/CFM or less and an airflow requirement of 250 CFM/ton or greater (§150.0(m)13D).
3. Two exceptions allow portions of a duct system to be uninsulated if specific conditions are met, as explained in Section 4.4.1 (Exceptions 1 and 2 to §150.0(m)1B).
4. Exceptions to requirements for a porous inner core flex duct is allowable if it has a nonporous layer or air barrier between the inner core and outer vapor barrier (§150.0(m)10).
5. There are changes to the mandatory air filtration requirements for space-conditioning systems with 10 feet or more of duct attached. The requirements affect the pressure drop and labeling of the filtration devices (§150.0(m)12).
6. Air filtration is now required on supply and balanced mechanical ventilation systems.
7. With the adoption of ASHRAE Standard 62.2-2016, higher mechanical ventilation rates will be required for single family units which vary by climate zone.
4.1.2.2 Prescriptive and Performance Compliance Approaches − §150.1
1. The refrigerant charge requirement in the prescriptive tables applies to all air conditioners and heat pumps, including small duct high, velocity systems §150.1(c)7A).
2. Central fan-integrated ventilation systems used in prescriptive compliance must meet the mandatory fan efficacy requirement of 0.45 watts/CFM or less for gas furnace air-handling units or 0.58 watts/CFM or less for air-handling units that are not gas furnaces (§150.1(c)10).
3. Heat pumps used in performance compliance may require HERS verification of the heating seasonal performance factor (HSPF) and heating capacity as explained in Section 4.2.3 (§150.1(b)3).
4. Whole house fans used in performance compliance may require HERS verification of the airflow rate and fan efficacy as explained in Section 4.3.3 (§150.1(b)3).
5. Central fan ventilation cooling systems used in performance compliance may require HERS verification of the system airflow rate and fan efficacy at ventilation speed, as explained in Section 4.3.3 (§150.1(b)3).
4.1.2.3 Additions and Alterations − §150.2
The Energy Standards requirements for altered or new HVAC systems in existing homes are summarized and discussed in Chapter 9.
Most heating and cooling equipment installed in new California homes is regulated by the National Appliance Efficiency Conservation Act (NAECA) and/or the California Appliance Efficiency Regulations (Title 20). Both the federal and state appliance standards apply to the manufacturing and sale of new equipment, whether for new construction, replacements, or repairs. The Appliance Efficiency Regulations are enforced at the point of sale (except central split-system air conditioners and central single package air conditioners, see Table 4-6), while the Energy Standards explained in this compliance manual are enforced by local enforcement agencies.
The equipment listed below is covered by the Appliance Efficiency Regulations. The manufacturer must certify that the equipment complies with the current Appliance Efficiency Regulations at the time of manufacture.
Appliances covered by the Appliance Efficiency Regulations include:
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a. Room air conditioners b. Room air-conditioning heat pumps c. Central air conditioners with a cooling capacity of less than 135,000 British thermal units per hour (Btu/hr) d. Central air conditioning heat pumps e. Gas-fired central furnaces |
f. Gas-fired boilers g. Gas-fired furnaces h. Gas-fired floor furnaces i. Gas-fired room heaters j. Gas-fired duct furnaces k. Gas-fired unit heaters |
The Appliance Efficiency Regulations do not require certification for:
1. Electric resistance space heaters.
2. Oil-fired wall furnaces, floor furnaces, and room heaters. (Some are voluntarily listed with certified gas-fired furnaces.)
Equipment that does not meet the federal appliance efficiency standards may not be sold in California. Any equipment covered by the Appliance Efficiency Regulations and sold in California must have the date of manufacture permanently displayed in an accessible place on that equipment. This date is frequently included as part of the serial number.
Generally, equipment manufactured before the effective date of a new standard may be sold and installed in California indefinitely as long as the performance approach demonstrates energy compliance of the building using the lower efficiency of the relevant appliances. An exception is central split-system air conditioners and central single package air conditioners installed in California. The U.S. Department of Energy (DOE) requires compliance with the minimum efficiencies specified in Table 4-6 at the time of installation.
The compliance and enforcement processes should ensure that all installed HVAC equipment regulated by the Appliance Efficiency Regulations is certified by the California Energy Commission.
4.1.3.1 Plan Review (Compliance)
During the plan review, the builder is responsible for demonstrating compliance with the Appliance Efficiency Regulations by providing the efficiency of the HVAC equipment that is to be installed. Typically, the builder does not identify the exact make or model at this point of the process. The plans examiner is responsible for verifying that the specified equipment efficiency complies with the Appliance Efficiency Regulations.
4.1.3.2 Field Inspection (Enforcement)
It is the field inspector’s responsibility to visually verify that the product information on the installed HVAC equipment matches the efficiency approved by the plans examiner. To simplify the inspection, the field inspector may reference the CF2R-MCH-01-H form submitted by the builder/installing contractor.