Table of Contents
4 Building HVAC Requirements 1
4.1 Overview ...................................................................................................................... 1
4.1.1 Introduction and Organization ..................................................................................... 1
4.1.2 What’s New for the 2019 Energy Standards ..................................................................... 1
4.1.3 Appliance Standards and Equipment Certification .................................................... 3
4.2 Heating Equipment ....................................................................................................... 4
4.2.1 Mandatory Measures for Heating Equipment............................................................. 4
4.2.2 Prescriptive Requirements for Heating Equipment .................................................. 13
4.2.3 Performance Compliance Options for Heating Equipment ....................................... 13
4.3 Cooling Equipment ..................................................................................................... 14
4.3.1 Mandatory Measures for Cooling Equipment ............................................................. 14
4.3.2 Prescriptive Requirements for Cooling Equipment ..................................................... 22
4.3.3 Performance Compliance Options for Cooling Equipment .......................................... 24
4.4 Air Distribution System Ducts, Plenums, Fans, and Filters ......................................... 26
4.4.1 Mandatory Measures for Air Distribution System Ducts, Plenums, Fans, andFilters…27
4.4.2 Prescriptive Requirements for Air Distribution System Ducts, Plenums, andFans …..53
4.4.3 Compliance Options for Air Distribution System Ducts, Plenums, and Fans……….. 59
4.4.4 Duct Installation Standards ........................................................................................ 63
4.5 Controls ....................................................................................................................... 69
4.5.1 Thermostats ............................................................................................................... 69
4.5.2 Zonal Control for Compliance Credit........................................................................... 70
4.6 Indoor Air Quality and Mechanical Ventilation ............................................................ 73
4.6.1 Compliance and Enforcement .............................................................................. 76
4.6.2 Typical Solutions for Single-Family Dwelling Unit Ventilation ............................... 79
4.6.3 Typical Solutions for Multifamily Dwelling Unit Ventilation.................................... 85
4.6.4 Dwelling Unit Ventilation Airflow Measurement .................................................... 86
4.6.5 Dwelling Unit Ventilation Rate (Section 4 of ASHRAE 62.2) ................................ 87
4.6.6 Dwelling Unit Mechanical Ventilation Energy Consumption ................................. 94
4.6.7 Local Exhaust (Section 5 of ASHRAE 62.2) ......................................................... 96
4.6.8 Other Requirements (Section 6 of ASHRAE 62.2) ............................................. 101
, Table of Contents
4.6.9 Air-Moving Equipment (Section 7 of ASHRAE 62.2)................................... 110
4.7 Alternative Systems .......................................................................................... 116
4.7.1 Hydronic Heating Systems ......................................................................... 116
4.7.2 Radiant Floor System ................................................................................. 120
4.7.3 Evaporative Cooling.................................................................................... 124
4.7.4 Ground-Source Heat Pumps ...................................................................... 126
4.7.5 Solar Space Heating ................................................................................... 126
4.7.6 Wood Space Heating .................................................................................. 126
4.7.7 Gas Appliances .......................................................................................... 129
4.7.8 Evaporatively Cooled Condensers ............................................................. 129
4.7.9 Nonducted Systems.................................................................................... 129
4.7.10 Ventilation Cooling ...................................................................................... 129
4.8 Refrigerant Charge ............................................................................................ 139
4.8.1 Refrigerant Charge Verification .................................................................. 139
4.9 Compliance and Enforcement ........................................................................... 147
4.9.1 Design-Phase Documentation .................................................................... 147
4.9.2 Construction-Phase Documentation ........................................................... 148
4.9.3 Field Verification and/or Diagnostic Testing................................................ 151
,Building HVAC Requirements – Overview
4 Building HVAC Requirements
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 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:
1. Section 4.2 – Heating Equipment.
2. Section 4.3 – Cooling Equipment.
3. Section 4.4 – Air Distribution System Ducts, Plenums, and Fans.
4. Section 4.5 – Controls.
5. Section 4.6 – Indoor Air Quality and Mechanical Ventilation.
6. Section 4.7 – Alternative Systems.
7. Section 4.8 – Compliance and Enforcement.
8. Section 4.9 – Refrigerant Charge.
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 2019 Energy Standards
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.
, Building HVAC Requirements – Overview
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 Building HVAC Requirements 1
4.1 Overview ...................................................................................................................... 1
4.1.1 Introduction and Organization ..................................................................................... 1
4.1.2 What’s New for the 2019 Energy Standards ..................................................................... 1
4.1.3 Appliance Standards and Equipment Certification .................................................... 3
4.2 Heating Equipment ....................................................................................................... 4
4.2.1 Mandatory Measures for Heating Equipment............................................................. 4
4.2.2 Prescriptive Requirements for Heating Equipment .................................................. 13
4.2.3 Performance Compliance Options for Heating Equipment ....................................... 13
4.3 Cooling Equipment ..................................................................................................... 14
4.3.1 Mandatory Measures for Cooling Equipment ............................................................. 14
4.3.2 Prescriptive Requirements for Cooling Equipment ..................................................... 22
4.3.3 Performance Compliance Options for Cooling Equipment .......................................... 24
4.4 Air Distribution System Ducts, Plenums, Fans, and Filters ......................................... 26
4.4.1 Mandatory Measures for Air Distribution System Ducts, Plenums, Fans, andFilters…27
4.4.2 Prescriptive Requirements for Air Distribution System Ducts, Plenums, andFans …..53
4.4.3 Compliance Options for Air Distribution System Ducts, Plenums, and Fans……….. 59
4.4.4 Duct Installation Standards ........................................................................................ 63
4.5 Controls ....................................................................................................................... 69
4.5.1 Thermostats ............................................................................................................... 69
4.5.2 Zonal Control for Compliance Credit........................................................................... 70
4.6 Indoor Air Quality and Mechanical Ventilation ............................................................ 73
4.6.1 Compliance and Enforcement .............................................................................. 76
4.6.2 Typical Solutions for Single-Family Dwelling Unit Ventilation ............................... 79
4.6.3 Typical Solutions for Multifamily Dwelling Unit Ventilation.................................... 85
4.6.4 Dwelling Unit Ventilation Airflow Measurement .................................................... 86
4.6.5 Dwelling Unit Ventilation Rate (Section 4 of ASHRAE 62.2) ................................ 87
4.6.6 Dwelling Unit Mechanical Ventilation Energy Consumption ................................. 94
4.6.7 Local Exhaust (Section 5 of ASHRAE 62.2) ......................................................... 96
4.6.8 Other Requirements (Section 6 of ASHRAE 62.2) ............................................. 101
, Table of Contents
4.6.9 Air-Moving Equipment (Section 7 of ASHRAE 62.2)................................... 110
4.7 Alternative Systems .......................................................................................... 116
4.7.1 Hydronic Heating Systems ......................................................................... 116
4.7.2 Radiant Floor System ................................................................................. 120
4.7.3 Evaporative Cooling.................................................................................... 124
4.7.4 Ground-Source Heat Pumps ...................................................................... 126
4.7.5 Solar Space Heating ................................................................................... 126
4.7.6 Wood Space Heating .................................................................................. 126
4.7.7 Gas Appliances .......................................................................................... 129
4.7.8 Evaporatively Cooled Condensers ............................................................. 129
4.7.9 Nonducted Systems.................................................................................... 129
4.7.10 Ventilation Cooling ...................................................................................... 129
4.8 Refrigerant Charge ............................................................................................ 139
4.8.1 Refrigerant Charge Verification .................................................................. 139
4.9 Compliance and Enforcement ........................................................................... 147
4.9.1 Design-Phase Documentation .................................................................... 147
4.9.2 Construction-Phase Documentation ........................................................... 148
4.9.3 Field Verification and/or Diagnostic Testing................................................ 151
,Building HVAC Requirements – Overview
4 Building HVAC Requirements
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 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:
1. Section 4.2 – Heating Equipment.
2. Section 4.3 – Cooling Equipment.
3. Section 4.4 – Air Distribution System Ducts, Plenums, and Fans.
4. Section 4.5 – Controls.
5. Section 4.6 – Indoor Air Quality and Mechanical Ventilation.
6. Section 4.7 – Alternative Systems.
7. Section 4.8 – Compliance and Enforcement.
8. Section 4.9 – Refrigerant Charge.
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 2019 Energy Standards
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.
, Building HVAC Requirements – Overview
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).
