4.1       Overview    

4.1.1    Introduction and Organization    

This chapter addresses the requirements for heating, ventilating, and air conditioning (HVAC) systems. The requirements are presented in this chapter so that it may serve as a single source of information for mechanical system designers and mechanical system installers, as well as energy consultants, 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.  When the building design does not achieve the minimum prescriptive requirements, then the compliance options may be used under the performance approach to achieve compliance. 

The chapter is organized under the following sections:

1.   Heating Equipment.  This section addresses the requirements for heating equipment, including mandatory measures, prescriptive requirements, and compliance options.

2.   Cooling Equipment. This section addresses cooling equipment requirements, including mandatory measures, prescriptive requirements, and compliance options.

3.   Air Distribution System Ducts, Plenums. This section covers mandatory requirements such as duct insulation, duct system construction practices and duct diagnostic testing.  This section also covers prescriptive specifications for access holes in the supply and return plenums to accommodate pressure and temperature measurements by installers and HERS raters.

4.   Controls. This section addresses mandatory requirements for thermostats and the compliance option for zonal controls.

5.   Indoor Air Quality and Mechanical Ventilation. This section covers mandatory requirements for indoor air quality including mechanical ventilation.

6.   Alternative Systems. This section covers a number of systems that are less common in California homes, including hydronic heating, radiant floor systems, evaporative cooling, gas cooling, ground-source heat pumps, and wood space heating.

7.   Compliance and Enforcement. In this section the documentation requirements at each phase of the project are highlighted.

8.   Refrigerant Charge. More information on the refrigerant charge verification procedures is included in this section.


Chapter 9 covers the heating and cooling requirements for additions to existing dwellings and for alterations to existing heating and cooling systems.

4.1.2    What’s New for the 2013 Standards    

The following is a summary of the new HVAC measures for the 2013 Standards, including new compliance options that provide greater flexibility in complying with the Standards when using the performance method.  See individual sections of this 'Manual for more detail.

Mandatory Features and Devices - Section 150.0

1.   The indoor design temperature for heating load calculations has been changed from 70 degrees to 68 degrees. [150.0(h)2]

2.   Air conditioning condensers are required to be located at least 5 feet from a clothes dryer vent outlet. [150.0(h)3]

3.   Gas furnaces must be designed and installed to meet the manufacturer’s maximum temperature split in heating mode. [150.0(h)4]

4.   There are some changes to the tables specifying mandatory minimum insulation on air conditioning refrigerant lines. [150.0(j)2C]

5.   There are some changes to the mandatory insulation protection for insulated pipes found outside conditioned space.  [150.0(j)3B]

6.   There is a new reference to a mandatory duct construction standard, ANSI/SMACNA-006-2006 HVAC Duct Construction Standard. [150.0(m)1]

7.   The mandatory minimum duct insulation R-value has been raised from R-4.2 to R-6, except for ducts located completely within directly conditioned space. [150.0(m)1]

8.   Duct sealing and field verification is now a mandatory measure (moved from the prescriptive packages) and can no longer be traded off by using the performance approach. [150.0(m)11]

9.   There are some changes to the target leakage rates for dwellings in multi-family buildings. [150.0(m)11]

10.  There are new mandatory requirements for filtration of all air passing through a ducted space conditioning system.  The requirements affect the design, efficiency, pressure drop and labeling of the filtration devices. [150.0(m)12]

11.  There are new mandatory requirements to ensure proper duct and filter grill sizing for forced air distribution systems that supply cooling to an occupiable space.  They include requirements for a hole for a static pressure probe (HSPP) and an option to either size return ducts based on prescriptive tables or field testing to meet airflow and fan watt requirements. [150.0(m)13]

12.  There are some new mandatory requirements for space cooling systems that utilize automatic zonal control to meet airflow and fan watt draw requirements. [150.0(m)15]

13.  The mandatory whole building ventilation requirement of ASHRAE 62.2 is now a HERS verified measure. [150.0(o)]


Prescriptive and Performance Compliance Approaches - Section150.1

1.   When higher than minimum SEER ratings are specified using the performance approach, installation of proper equipment is now a HERS verified measure.  Previously this only applied to high EER equipment.  [150.1(b)4Bi

2.   There is now only one set of prescriptive measures (prescriptive package A).  [150.1(c)]

3.   There is a new allowance for supplemental heating systems.  It includes limitations on size and requirements for timing controls.  [150.1(c)6]

4.   The temperature split approach to minimum airflow verification for refrigerant charge verification has been omitted.  This reduces the number of required measurement access holes from two to one. [150.1(c)7Aia]

5.   Some package units, mini-splits and variable refrigerant flow systems will be required to demonstrate proper refrigerant charge using a weigh-in approach and must be verified by a HERS rater.  [150.1(c)7Aii]

6.   Ducts not insulated because they are deemed to be in directly conditioned space must be verified by a HERS rater utilizing the duct leakage to outside procedures.  [150.1(c)9]

7.   There is a new prescriptive requirement in climate zones 8 through 14 for whole house fans designed to provide ventilation cooling.  [150.1(c)12]

8.   When homes utilizing the prescriptive approach have automatic zonal control, they are prohibited from using bypass ducts that divert supply air directly back to the return air stream.  Using the performance approach, there is an energy penalty for systems choosing to utilize bypass ducts for zonal control. [150.1(c)13]

9.   Maximum Rated Total Cooling Capacity compliance credit has been deleted.


Additions and Alterations - Section 150.2

The new requirements in the 2013 Standards for HVAC systems in homes that are altered or added to are summarized and discussed in Chapter 9.

4.1.3    Common System Types    

The typical new California home in the central valley and the desert has a gas furnace and a split system air conditioner. Both heating and cooling is typically distributed to each of the rooms through air ducts. Most of the mandatory measures and prescriptive requirements are based on this type of system.  In some areas, a heat pump provides both heating and cooling, eliminating the furnace. In coastal climates and in the mountains, air conditioning is rare and most new homes are heated by gas furnaces.

Although the Standards focus on the typical system, they also apply to other systems as well, including some radiant hydronic systems where hot water is distributed to parts of the home to provide at least some of the heat to conditioned space.

Electric resistance systems are used in some areas and applications, although it is difficult for them to comply under the Standards.

Ground-source or water source heat pump (geo-exchange) systems are also used, especially in areas where there is no gas service.  Unlike the more typical air source systems, these utilize water circulated underground or in large ponds or lakes as the heat source (in heating mode) and heat sink (in cooling mode).

This chapter focuses mostly on typical systems, but a section is provided to deal with the alternative systems as well.

4.1.4    California Appliance Standards and Equipment Certification    

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 manufacture of new equipment and are applicable for equipment used in replacements, repairs or for any other purpose. The Appliance Efficiency Regulations are enforced at the point of sale, while the Energy Efficiency Standards explained this compliance 'manual are enforced by local enforcement agencies.

The following types of equipment (in the list below) are covered by the Appliance Efficiency Regulations. For this equipment, 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:

1.     Room air conditioners

2.     Room air conditioning heat pumps

3.     Central air conditioners with a cooling capacity of less than 135,000 Btu/hr

4.     Central air conditioning heat pumps

5.     Gas-fired central furnaces

6.     Gas-fired boilers

7.     Gas-fired furnaces

8.     Gas-fired floor furnaces

9.     Gas-fired room heaters

10.   Gas-fired duct furnaces

11.   Gas-fired unit heaters

The Appliance Efficiency Regulations do not require certification for:

Electric resistance space heaters

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.

Note: Equipment manufactured before the effective date of a new standard may be sold and installed in California indefinitely, as long as the performance and prescriptive approach demonstrates energy compliance of the building using the lower efficiency of the relevant appliances.

The compliance and enforcement process should ensure that all installed HVAC equipment regulated by the Appliance Efficiency Regulations is certified to the Energy Commission.

Plan Review Process (Compliance)

During the plan review process builder must show 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 during the process.  The Plans Examiner is responsible for verifying that the specified equipment efficiency complies with the Appliance Efficiency Regulations. 

Field Inspection (Enforcement)

It is the responsibility of The Field Inspector to visually verify that the product information on the installed HVAC equipment matches the efficiency that was approved by the Plans Examiner.  To facilitate the inspection process the Field Inspector may reference the CF2R-MCH-01-H form submitted by the builder/installing contractor.  Additionally, the Field Inspector must also verify that the installed HVAC equipment is certified to the Energy Commission.  The Field Inspector, at their discretion, may require the builder/installing contractor to provide a print out from the Energy Commission Appliance Efficiency Database of certified equipment listing the same make and model that is installed.

If the specifications labeled on the HVAC equipment do not match the equipment specifications on the Energy Commission Appliance Efficiency Database, the Inspector shall issue a correction notice to the builder/installing contractor.  The following statement may be used as a correction notice.

4.1.5    Federal Appliance Standards (NAECA)   

On June 27, 2011 the U.S. Department of Energy adopted new federal air conditioner efficiency standards.  For California those federal standards require efficiencies of SEER 14 and EER 12.2 for central split system air conditioners smaller than 45,000 Btu/hr (a SEER 14 and EER of 11.7 is required for larger central split system air conditioners).  The new federal standards go into effect on January 1, 2015, which is six months after the July 1, 2014 effective date of the 2013 Standards.  For performance approach simulations for projects subject to building permits (newly constructed buildings, additions and alterations to existing buildings) applied for after December 31, 2014, the compliance software will use a standard design that has been updated for the new federal standards. 

In the past production builders have found it to be disruptive to have federal appliance efficiency standards change in the middle of a California Building Energy Efficiency Standards code cycle.  They have preferred that for the entire period of the code cycle, that energy performance compliance be determined based on compliance both with the California building standards requirements plus the federal appliance efficiency standards.  In that way they can build out their subdivisions with measures that remain consistent throughout the code cycle, rather than have to track and cope with a change in those measures in the middle of the cycle, which results in different customers receiving homes with different levels of energy efficiency.  Other builders may prefer to cope with that change in the middle of the cycle, and build homes prior to the effective date of the federal standards that have a worse efficiency (and likely lower construction cost) than the homes that they build after the effective date of the federal standards. 

The Energy Commission will direct compliance software developers to provide either approach to builders so they can choose which approach to take.  Based on the builder’s choice the software will automatically determine whether compliance has been achieved. 

For projects with permits applied for between July 1, 2014 and December 31, 2014 builders have two choices:

Option 1:  Choose to Change the Efficiency for Their Homes in the Middle of the Code Cycle.  Install equipment that meets the SEER 13 requirements of the current federal air conditioner standards.  The software will compare the efficiency of the installed equipment against a standard design of SEER 13 to determine to what extent the building complies with the Building Standards.  Starting January 1, 2015 the standard design will change to match the new federal air conditioner standards.  After that point in time builders will have to improve the efficiency of the air conditioners they install to be equal to or better than the new federal air conditioner standards, and the efficiency measures required in the rest of the house may have to change to comply with the Building Standards depending on the air conditioner efficiencies that they choose. 

Option 2:  Choose to Build a Constant Efficiency for their Homes Throughout the Code Cycle.  Install higher efficiency air conditioners that meet the new federal air conditioner efficiency standards.  The software will compare the higher efficiency of the installed air conditioner against a standard design that meets the new federal air conditioner efficiency standards.  Builders will be able to install the same air conditioner efficiency before and after the federal air conditioner standards effective date; expectations are that the construction costs will come down after the effective date as manufacturers are competing to offer equipment compliant with the new federal standards at lowest cost – this cost competition also may occur earlier than the effective date, as manufacturers endeavor to gain a competitive advantage ahead of the effective date.  Builders will be able to install other building energy efficiency measures in their homes throughout the code cycle without having to have a disruptive change in what their crews are installing, and can avoid customers receiving homes that have different efficiency levels and measures in the middle of the code cycle.