The provisions contained in this appendix are not mandatory unless specifically referenced in the adopting ordinance.
(This appendix is not part of this code. It is merely informative and does not contain requirements necessary for conformance to the code. It has not been processed according to the ANSI requirements for a code and may contain material that has not been subject to public review or a consensus process. Unresolved objectors on informative material are not offered the right to appeal at ASHRAE or ANSI.)
The purpose of this appendix is to provide users of the prescriptive energy path of the IECC a correlated version of ANSI/ASHRAE/ICC/USGBC/IES Standard 189.1, Chapter 7 (Section 7), that facilitates the use of the prescriptive provisions of the IECC without directly relying on the energy provisions of ANSI/ASHRAE/IES Standard 90.1. Section numbers in this appendix, unless otherwise specified, refer to Standard 189.1. Where ASHRAE standards are referenced in this appendix, ASHRAE provides free online access to readonly versions of the standards. See https://www.ashrae.org/standards-research-technology/standards--guidelines/other-ashrae-standards-referenced-in-code.
DEFINITIONS APPLICABLE TO THIS APPENDIX
air, outdoor: see ANSI/ASHRAE Standard 62.1.
building envelope: see ANSI/ASHRAE/IES Standard 90.1.
dynamic glazing: see ANSI/ASHRAE/IES Standard 90.1.
enclosed space: see ANSI/ASHRAE/IES Standard 90.1.
fenestration: see ANSI/ASHRAE/IES Standard 90.1.
vertical fenestration: see ANSI/ASHRAE/IES Standard 90.1.
fenestration area: see ANSI/ASHRAE/IES Standard 90.1.
gross wall area: see ANSI/ASHRAE/IES Standard 90.1.
lighting power allowance: see ANSI/ASHRAE/IES Standard 90.1.
roof: see ANSI/ASHRAE/IES Standard 90.1.
service water heating: see ANSI/ASHRAE/IES Standard 90.1.
single-rafter roof: see ANSI/ASHRAE/IES Standard 90.1.
skylight: see ANSI/ASHRAE/IES Standard 90.1.
space: see ANSI/ASHRAE/IES Standard 90.1.
semiheated space: see ANSI/ASHRAE/IES Standard 90.1.
This section specifies prescriptive requirements for energy efficiency for buildings and appliances, for on-site renewable energy systems, and for energy measuring.
The energy systems shall comply with Sections 701.3.2 (7.3.2) through 701.3.4 (7.3.4) and with the International Energy Conservation Code (IECC), Sections C402 through C405. In addition, commercial buildings shall comply with the IECC, Section C406, and tenant spaces shall comply with the IECC, Section C406.1.1.
H401.1 (H4.1)On-Site Renewable Energy Systems.
H401.2 (H4.2)Building Envelope.
H401.2.1 (H4.2.1)Continuous Air Barrier.
The exceptions to the requirement for a continuous air barrier in the IECC, Sections C402.5.1, for specific climate zones and constructions shall not apply.
H401.2.2 (H4.2.2)Building Envelope Requirements.
The building envelope shall comply with the requirements in the IECC, Table C402.1.4, with the following modifications to values in the table.
For the opaque elements, each U-factor, C-factor, and F-factor in the table shall be reduced by 5%. For vertical fenestration and skylights, each U-factor in the IECC, Table C402.4, shall be reduced by 5%. For skylights and east-oriented and west-oriented vertical fenestration, each solar heat gain coefficient (SHGC) in the IECC, Table C402.4, shall be reduced by 5%. These adjustments shall also be applicable where the intent is to comply with the component performance alternative of the IECC, Sections C402.1.5.
1.The U-factor, C-factor, or F-factor shall not be modified where the corresponding R-value requirement is designated as “NR” (no requirement) in the IECC, Table C402.4.
2.The SHGC shall not be modified where the SHGC requirement is designated as “NR” (no requirement) in the IECC, Table C402.4.
3.Spaces that meet the requirements of Section 801.4.1 (8.4.1), regardless of space area, are exempt from the SHGC criteria for skylights.
H401.2.3 (H4.2.3)Single-Rafter Roof Insulation.
H401.2.4 (H4.2.4)Air Curtains.
Where provided, air curtains shall comply with Section 701.4.2.4 (188.8.131.52).
H401.2.5 (H4.2.5)High-Speed Doors.
High-speed doors that are intended to operate, on average, at least 75 cycles per day shall not exceed a maximum U-factor of 1.20 Btu/h·ft2·°F (6.81 W/m2·K). Opening rate, closing rate, and average cycles per day shall be included in the construction drawings. IECC, Table C402.1.3, shall not apply for high-speed doors complying with all criteria in this section.
H401.2.6 (H4.2.6)Vertical Fenestration Area.
H401.2.7 (H4.2.7)Permanent Projections.
Vertical fenestration shall comply with Section 701.4.2.6 (184.108.40.206).
H401.2.8 (H4.2.8)SHGC of Vertical Fenestration.
Vertical fenestration shall comply with the IECC, Table C402.4.
H401.2.9 (H4.2.9)Building Envelope Trade-Off Option.
The vertical fenestration shall comply with either (a) or (b):
a.AW ≤ (AN + AS)/4 and AE ≤ (AN + AS)/4
b.AW × SHGCW ≤ (AN × SHGCC + AS × SHGCC)/6 and AE × SHGCE ≤ (AN × SHGCC + AS × SHGCC)/6
SHGCX = the SHGC for orientation x that complies with Section H401.2.7 (H4.2.7).
SHGCC = the SHGC criteria for each climate zone from Section H401.2.2 (H4.2.2).
AX = fenestration area for orientation x.
N = north (oriented less than 45 degrees of true north).
S = south (oriented less than 45 degrees of true south).
E = east (oriented less than or equal to 45 degrees of true east).
W = west (oriented less than or equal to 45 degrees of true west).
1.Buildings with shade on 75% of the west- and east-oriented vertical fenestration areas from permanent projections, existing buildings, existing permanent infrastructure, or topography at 9 a.m. and 3 p.m. on the summer solstice (June 21 in the northern hemisphere).
2.Alterations and additions with no increase in vertical fenestration area.
3.Buildings where the west- and east-oriented vertical fenestration areas do not exceed 20% of the gross wall area for each of those façades, and the SHGC on those façades is not greater than 90% of the criteria in Section H401.2.2 (H4.2.2).
4.Buildings in Climate Zone 8.
H401.3 (H4.3)Heating, Ventilating, and Air Conditioning.
H401.3.1 (H4.3.1)Minimum Equipment Efficiencies for the Alternate Renewables Approach.
H401.3.2 (H4.3.2)Ventilation Controls for Densely Occupied Spaces.
The requirements in this section supersede those in the IECC, Section C403.7.1. Demand control ventilation (DCV) shall be provided for densely occupied spaces served by systems with one or more of the following:
a.An air-side economizer
b.Automatic modulating control of the outdoor air dampers
c.A design outdoor airflow greater than 1000 cfm (500 L/s)
The DCV system shall be designed to be in compliance with ANSI/ASHRAE Standard 62.1, Section 6.2.7. Occupancy assumptions shall be shown in the design documents for spaces provided with DCV. All CO2 sensors used as part of a DCV system or any other system that dynamically controls outdoor air shall meet the following requirements:
a.Spaces with CO2 sensors or air-sampling probes leading to a central CO2 monitoring station shall be provided with at least one sensor or probe for each 10,000 ft2 (1000 m2) of floor space. Sensors or probes shall be installed between 3 and 6 ft (1 and 2 m) above the floor.
b.CO2 sensors shall have a rated accuracy of ±50 ppm at 1000 ppm.
c.Outdoor air CO2 concentrations shall be determined by one of the following:
1.Outdoor air CO2 concentrations shall be dynamically measured using one or multiple CO2 sensors. The CO2 sensor locations shall be identified on the construction documents.
2.When documented statistical data are available on the local ambient CO2 concentrations, a fixed value typical of the location where the building is located shall be allowed in lieu of an outdoor sensor.
d.Occupant CO2 generation rate assumptions shall be shown in the design documents.
1.Systems with exhaust air energy recovery complying with Section H401.3.6 (H4.3.6).
2.Systems with a design outdoor airflow less than 750 cfm (350 L/s).
3.Spaces where more than 75% of the space design outdoor airflow is used as makeup air or transfer air to provide makeup air for other spaces.
4.Spaces with one of the following occupancy categories as defined in ASHRAE Standard 62.1: cells in correctional facilities; daycare sickrooms; science laboratories; barbershops; beauty and nail salons; and bowling alleys (seating).
H401.3.3 (H4.3.3)Duct Leakage Tests.
Leakage tests shall be performed in compliance with the requirements in ANSI/ASHRAE/IES Standard 90.1, Section 220.127.116.11.2, with the following modification. Ductwork that is designed to operate at static pressures in excess of 2 in. of water (500 Pa), and all ductwork located outdoors, shall be leak-tested according to industry-accepted test procedures.
a.Rooftop units with a capacity of less than 54,000 Btu/h (16 kW) shall have two stages of capacity control, with the first stage controlling the economizer and the second stage controlling mechanical cooling. Units with a capacity equal to or greater than 54,000 Btu/h (16 kW) shall comply with the staging requirements defined in the IECC, Section C403.8.
b.For systems that control to a fixed leaving air temperature (i.e., variable-air-volume [VAV] systems), the system shall be capable of resetting the supply air temperature up at least 5°F (3°C) during economizer operation.
All of the exceptions in the IECC, Section C403.5, shall apply except as modified by the following.
a.Where the reduced renewable approach defined in Section 701.4.1.1.2 (18.104.22.168.2) is used, the IECC, Section C403.5, Exception 5, shall be permitted to eliminate the economizer requirement, provided the requirements in the IECC, Table C403.5(2), are applied to the efficiency requirements required by Section 701.4.1.1.2 (22.214.171.124.2). If the standard renewable approach is chosen, as defined in Section 701.4.1.1.2 (126.96.36.199.2), then the requirements in the IECC, Table C403.5(2), shall be applied to the efficiency requirements in the IECC, Tables C403.3.2(1) through C403.3.2(10).
b.For water-cooled units with a capacity less than 54,000 Btu/h (16 kW) that are used in systems where heating and cooling loads are transferred within the building (i.e., water-source heat pump systems), the requirement for an air or water economizer can be eliminated if the con- denser-water temperature controls are capable of being set to maintain full-load heat rejection capacity down to a 55°F (12°C) condenser-water supply temperature, and the HVAC equipment is capable of operating with a 55°F (12°C) condenser-water supply temperature.
H401.3.5 (H4.3.5)Fan System Power and Efficiency
H401.3.5.1 (H188.8.131.52)Fan System Power Limitation.
Systems shall have fan power limitations 10% below the limitations specified in the IECC, Table C403.8.1(1). This requirement supersedes the requirement in the IECC, Section C403.8, and the IECC, Table C403.8.1(2). All exceptions in the IECC, Section C403.8, shall apply.
H401.3.5.2 (H184.108.40.206)Fan Efficiency.
The fan efficiency requirements defined in the IECC, Section C403.8.3, shall be used, except that the total efficiency of the fan at the design point of operation shall be within ten percentage points of the maximum total efficiency of the fan. All exceptions in the IECC, Section C403.8.3, shall apply.
H401.3.6 (H4.3.6)Exhaust Air Energy Recovery.
The exhaust air energy recovery shall comply with the requirements defined in the IECC, Section C403.7.4, including the requirements in Tables C403.7.4(1) and C403.7.4(2). The energy recovery effectiveness shall not be less than 60%, and this shall supersede the requirement of the IECC.
H401.3.7 (H4.3.7)Kitchen Exhaust Systems.
H401.3.8 (H4.3.8)Duct Insulation.
H401.3.9 (H4.3.9)Automatic Control of HVAC and Lights in Hotel/Motel Guest Rooms.
Controls in hotel and motel guest rooms shall comply with Section 701.4.3.10 (220.127.116.11).
H401.3.10 (H4.3.10)HVAC Equipment Performance Requirements.
Note: Some 2018 IECC minimum efficiency requirements are below Federal minimum standards. Users may want to verify applicable requirements.
H401.4 (H4.4)Service Water Heating.
The service water heating shall comply with the IECC, Section C404 with the following modifications and additions.
H401.4.1 (H4.4.1)Equipment Efficiency for the Alternate Renewables Approach.
Building projects complying with the Alternate Renewables Approach in Section 701.4.1.1.2 (18.104.22.168.2) shall comply with the applicable equipment efficiency requirements in Normative Appendix B, Table B101.9 (B-9), and the applicable ENERGY STAR® requirements in Section 701.4.7.3 (22.214.171.124). These requirements supersede the requirements in the IECC, Table C404.2.
H401.4.2 (H4.4.2)Insulation for Spa Pools.
Insulation for spa pools shall comply with Section 701.4.4.2 (126.96.36.199).
H401.5.1 (H4.5.1)Lighting Power Allowance
H401.5.1.1 (H188.8.131.52)Interior Lighting Power Densities (LPDs).
The interior lighting power allowance shall comply with Section 701.4.6.1.1 (184.108.40.206.1).
H401.5.1.2 (H220.127.116.11)Exterior LPDs.
The exterior lighting power allowance shall be determined using the IECC, Section C405.4.1, with the following modification. The LPDs from the IECC, Table C405.4.2(2), shall be multiplied by the applicable LPD Factor from Table 701.4.6.1.2 (18.104.22.168.2).
H401.5.2 (H4.5.2)Occupancy Sensor Controls with Multilevel Switching or Dimming.
Lighting in commercial and industrial storage stack areas shall comply with Section 701.4.6.2 (22.214.171.124).
H401.5.3 (H4.5.3)Automatic Controls for Egress and Security Lighting.
Automatic controls for egress and security lighting shall comply with Section 701.4.6.3 (126.96.36.199).
H401.5.4 (H4.5.4)Controls for Exterior Sign Lighting.
Controls for exterior sign lighting shall comply with Section 701.4.6.4 (188.8.131.52).
H401.5.5 (H4.5.5)Parking and Outdoor Sales Lighting.
This section supersedes the IECC, Section C405.4.2, for lighting serving uncovered parking areas. Outdoor luminaires serving uncovered parking areas and open areas in outdoor sales lots shall be controlled by all of the following:
a.Luminaires shall be controlled by a device that automatically turns off the luminaire during daylight hours.
b.Luminaires shall be controlled by a timeclock or other control that automatically turns off the luminaire according to a timed schedule.
c.For luminaires having a rated input wattage of more than 50 W and where the bottom of the luminaire is mounted 24 ft (7.3 m) or less above the ground, the luminaires shall be controlled by one or more devices that automatically reduce lighting power of each luminaire by a minimum of 50% when there is no activity detected in the controlled zone for a period no longer than 15 minutes. No more than 1500 input watts of lighting power shall be controlled together.
1.Lighting serving street frontage for vehicle sales lots.
2.Lighting for covered vehicle entrances or exits from buildings or parking structures where required for safety, security, or eye adaptation.
H401.5.6 (H4.5.6)Other Equipment.
H401.5.6.1 (H184.108.40.206)Equipment Efficiency for the Alternate Renewables Approach.
Building projects complying with the Alternate Renewables Approach in Section 701.4.1.1.2 (220.127.116.11.2) shall comply with the applicable equipment efficiency requirements in Normative Appendix B and the applicable ENERGY STAR requirements in Section 701.4.7.3.2 (18.104.22.168.2).
H401.5.6.2 (H22.214.171.124)Supermarket Heat Recovery.
Supermarkets shall comply with Section 701.4.7.2 (126.96.36.199), as applicable.
H401.5.6.3 (H188.8.131.52)ENERGY STAR Equipment.
All building projects shall comply with Section 701.4.7.3 (184.108.40.206).
H401.5.6.4 (H220.127.116.11)Programmable Thermostats.
Residential programmable thermostats shall comply with Section 701.4.7.4 (18.104.22.168).
H401.5.6.5 (H22.214.171.124)Refrigerated Display Cases.
Refrigerated display cases shall comply with Section 701.4.7.5 (126.96.36.199).
2018 International Green Construction Code