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Requirements
Case 1. Single Family
Meet all of the following requirements for local exhaust and outdoor air ventilation including the requirements of ASHRAE 62.2 – 2010, sections 4, 5 and 7 and Section 1503.4 of the 2009 International Residential Code (IRC), including:- Local Exhaust. Meet all the following requirements: Design and install local exhaust systems in all bathrooms (including half-baths) and the kitchen to meet the requirements of ASHRAE Standard 62.2–2010, Sections 5 and 7 or local equivalent, whichever is more stringent. Sample requirements that relate to minimum intermittent local exhaust flow rates are shown in Table 1. Exhaust air to the outdoors. Do not route exhaust ducts to terminate in attics or interstitial spaces. Recirculating range hoods or recirculating over-the-range microwaves do not satisfy the kitchen exhaust requirements. Use ENERGY STAR–labeled bathroom exhaust fans in all bathrooms (including half-baths) or performance equivalent for projects outside the U.S. A HRV or ERV can be used to exhaust single or multiple bathrooms if it has an efficacy level meeting the ENERGY STAR Technical Specifications for Residential Heat-Recovery Ventilators and Energy-Recovery Ventilators (H/ERVs) Version 2.0 as certified by HVI. For exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (188 liters per second), provide makeup air at a rate approximately equal to the exhaust air rate. Makeup air systems must have a means of closure and be automatically controlled to start and operate simultaneously with the exhaust system.
- Whole House Mechanical Ventilation. Design and install a whole-house mechanical ventilation system that complies with ASHRAE Standard 62.2–2010, Sections 4 and 7 or local equivalent, whichever is more stringent. Whole house ventilation fans must be rated for sound at a maximum of 1.0 sone per ASHRAE 62.2–2010, Section 7.2.1. Remote mounted fans need not meet these sound requirements.
The ASHRAE options can be summarized as follows:
- Continuous ventilation. Meet the ventilation requirements. Simplified minimum air-flow requirements are shown in Table 2.
- Intermittent ventilation. Use ASHRAE Standard 62.2–2010, Equation 4.2, to demonstrate adequate ventilation air flow.
- Any passive ventilation system must be approved and verified by a licensed HVAC engineer as providing ventilation equivalent to that achieved by continuous ventilation systems.
Table 1. Minimum air-flow requirements for intermittent local exhaust
|
Minimum air flow |
|---|---|
Kitchen |
100 cfm (47 liters per second); vented range hood required if continuous exhaust fan flow rate is less than 5 kitchen air changes per hour |
Bathroom, half-bath |
50 cfm (23 liters per second) |
Table 2a. Simplified minimum air-flow requirements (cfm) for continuous ventilation systems
Conditioned floor area (ft2) |
Bedrooms |
||||
|---|---|---|---|---|---|
0, 1 |
2, 3 |
4, 5 |
6, 7 |
> 7 |
|
≤ 1,500 |
30 |
45 |
60 |
75 |
90 |
1,501–3,000 |
45 |
60 |
75 |
90 |
105 |
3,001–4,500 |
60 |
75 |
90 |
105 |
120 |
4,501–6,000 |
75 |
90 |
105 |
120 |
135 |
6,001–7,500 |
90 |
105 |
120 |
135 |
150 |
> 7,500 |
105 |
120 |
135 |
150 |
165 |
Table 2b. Simplified minimum air-flow requirements (liters per second) for continuous ventilation systems
Conditioned floor area (m2) |
Bedrooms |
||||
|---|---|---|---|---|---|
0, 1 |
2, 3 |
4, 5 |
6, 7 |
> 7 |
|
≤ 139 |
14 |
21 |
28 |
35 |
42 |
140 – 279 |
21 |
28 |
35 |
42 |
49 |
280 – 418 |
28 |
35 |
42 |
49 |
56 |
419 – 557 |
35 |
42 |
49 |
56 |
63 |
558 – 697 |
42 |
49 |
56 |
63 |
70 |
> 698 |
49 |
56 |
63 |
70 |
77 |
Case 2. Multifamily
Design and install a whole-unit ventilation system for each individual dwelling unit that complies with the requirements of ASHRAE Standard 62.2–2010 (with errata) or local equivalent, whichever is more stringent, and all local exhaust requirements for Single Family section, above. Major components of the standard are summarized below.- Provide outdoor air to each unit directly from the outdoors. Project teams using exhaust ventilation systems must specify how outside air is delivered at the flow rate required by ASHRAE 62.2–2010. Do not use systems that rely on transfer air from pressurized hallways or corridors, adjacent dwelling units, attics, etc.
- For continuous ventilation systems, meet the requirements of ASHRAE 62.2–2010 shown in Table 2, Continuous in-unit ventilation fans must be rated for sound at a maximum of 1.0 sone, per ASHRAE 62.2–2010, Section 7.2.1. Remote mounted fans need not meet these sound requirements.
- For intermittent ventilation systems, install fans to meet ASHRAE Standard 62.2–2010. The fan flow rate must be equal to the outdoor air flow requirements multiplied by the fan flow rate multiplier. The system must be designed such that it can operate automatically based on a timer. Fans must be rated for sound at a maximum of 1.0 sone. Remote mounted fans need not meet these sound requirements.
- As applicable, follow the restrictions on system types for hot, humid climates and very cold climates. In hot, humid climates, whole-house mechanical net exhaust flow must not exceed 7.5 cfm per 100 square feet (38 liters per second per 100 square meters) of conditioned floor area. In very cold climates, mechanical supply-only systems must not exceed 7.5 cfm per 100 square feet (38 liters per second per 100 square meters). See ASHRAE 62.2–2010, Sections 4.5 and 8, for more details and climate categories.
- Locate air inlets that are part of the ventilation design at least 10 feet (3 meters) from known sources of contamination, such as a stack, vent, exhaust hood, or vehicle exhaust. Place the intake such that entering air is not obstructed by snow, plantings, or other material. Forced air inlets must be covered by screens to exclude rodents and insects (mesh not larger than ½ inch or 13 millimeters). See ASHRAE 62.2–2010, Section 6.8, for more details and a list of exceptions.
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Cost estimates for this credit
On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.
Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.
This information is also available in a full PDF download in The Cost of LEED v4 report.
Learn more about The Cost of LEED v4 »Frequently asked questions
See all forum discussions about this credit »Addenda
10/14/2019 – Updated: 10/14/2019
Regional ACP
Description of change:
Campus Applicable
No
Internationally Applicable:
Yes
10/2/2017 – Updated: 10/2/2017
Rating System Correction
Description of change:
Under Case 1, first sentence, revise IRC section reference from Section 1504.4 to Section 1503.4.
Campus Applicable
No
Internationally Applicable:
No
10/17/2016 – Updated: 11/9/2016
Reference Guide Correction
Description of change:
Under Whole-House Ventilation, Step 2. Select Ventilation
Remove the 3rd bullet that states "Multifamily midrise and attached single-family home projects using exhaust-only ventilation must specify how outside air is delivered to the living space at the flow rate required by ASHRAE 62.2–2010. Outside air cannot come from interior hallways or any other interior space, including adjacent units (see Further Explanation, Multifamily Ventilation Strategies). Trickle vents are a common strategy for providing make-up air. Products that allow the occupant to partially or fully close the trickle vents are recommended."
Under Further Explanation, Multifamily Ventilation Strategies
Remove the following from the 3rd paragraph "multiple trickle vents in each unit or with". The sentence should read "Outside air intakes to individual units can be accomplished through an outside air duct directed to the return plenum of the HVAC system."
Remove the 3rd bullet that states "Multifamily midrise and attached single-family home projects using exhaust-only ventilation must specify how outside air is delivered to the living space at the flow rate required by ASHRAE 62.2–2010. Outside air cannot come from interior hallways or any other interior space, including adjacent units (see Further Explanation, Multifamily Ventilation Strategies). Trickle vents are a common strategy for providing make-up air. Products that allow the occupant to partially or fully close the trickle vents are recommended."
Under Further Explanation, Multifamily Ventilation Strategies
Remove the following from the 3rd paragraph "multiple trickle vents in each unit or with". The sentence should read "Outside air intakes to individual units can be accomplished through an outside air duct directed to the return plenum of the HVAC system."
Campus Applicable
No
Internationally Applicable:
No
10/17/2016 – Updated: 11/9/2016
Rating System Correction
Description of change:
Delete the following sentence:
"Project teams using exhaust ventilation systems must specify how outside air is delivered at the flow rate required by ASHRAE 62.2–2010."
"Project teams using exhaust ventilation systems must specify how outside air is delivered at the flow rate required by ASHRAE 62.2–2010."
Campus Applicable
No
Internationally Applicable:
No
7/1/2016 – Updated: 7/15/2016
Reference Guide Correction
Description of change:
Under Step-by-Step, Whole-House Ventilation, Step 2, delete the third bullet: "Multifamily midrise and attached single-family home projects using exhaust-only ventilation must specify how outside air is delivered to the living space at the flow rate required by ASHRAE 62.2–2010. Outside air cannot come from interior hallways or any other interior space, including adjacent units (see Further Explanation, Multifamily Ventilation Strategies). Trickle vents are a common strategy for providing make-up air. Products that allow the occupant to partially or fully close the trickle vents are recommended."
Under Further Explanation, Multifamily ventilation strategies, in the third paragraph, modify the first sentence: "Consider providing outside air through multiple trickle vents in each unit or with an outside air duct directed to the return plenum of the HVAC system.”
Under Further Explanation, Multifamily ventilation strategies, in the third paragraph, modify the first sentence: "Consider providing outside air through multiple trickle vents in each unit or with an outside air duct directed to the return plenum of the HVAC system.”
Campus Applicable
No
Internationally Applicable:
No
1/4/2016 – Updated: 4/5/2016
Rating System Correction
Description of change:
Under requirement 1 for Local Exhaust, revise the third paragraph so it reads: Use ENERGY STAR–labeled bathroom exhaust fans in all bathrooms (including half-baths) or performance equivalent for projects outside the U.S. A HRV or ERV can be used to exhaust single or multiple bathrooms if it has an efficacy level meeting the ENERGY STAR Technical Specifications for Residential Heat-Recovery Ventilators and Energy-Recovery Ventilators (H/ERVs) Version 2.0 as certified by HVI.”
Campus Applicable
No
Internationally Applicable:
No
4/2/2014
LEED Interpretation
Inquiry:
Can Passive House projects use the PHI or PHIUS + approach to kitchen exhaust, as opposed to meeting ASHRAE 62.2 requirements of 5 ACH of the kitchen volume for continuous ventilation?
Ruling:
Projects that are PHI or PHIUS + certified are permitted to use a continuous kitchen exhaust rate of 25 CFM per 2009 IRC table M1507.3, powered by an energy or heat recovery ventilator, but only if there are no combustion appliances in the kitchen (such as gas ovens or ranges).
Additional note: This ruling aligns with EPA ENERGY STAR for Homes and DOE Challenge Home ruling 00343, while adding in the requirement that no appliances can be combustion fueled.
**Updated 10/14/19 to include PHI
Campus Applicable
No
Internationally Applicable:
Yes
4/5/2016
LEED Interpretation
Inquiry:
Which LEED v4 Homes credit and prerequisite requirements can be automatically met by the EPA Indoor airPLUS program?
Ruling:
Projects that earn the EPA Indoor airPLUS label, based on Indoor airPLUS Version 1 (Rev 03) Construction Specifications automatically meet the requirements of the following prerequisites and credits:
EQ prerequisite Ventilation;
EQ prerequisite Combustion venting;
EQ prerequisite Garage pollutant protection;
EQ prerequisite Radon-resistant construction;
EQ prerequisite Air filtering;
EQ prerequisite Environmental tobacco smoke;
EQ credit Contaminant control, Option 3. Preoccupancy Flush (0.5 points);
EQ credit Enhanced combustion venting, Option 2. Enhanced combustion venting measures (1 point);
EQ credit Enhanced garage pollutant protection, Case 1. Single Family, Option 1. Exhaust Fan in Garage (1 point)
MR credit Durability management verification (1 point)
SS credit Nontoxic pest control (1 point) , measure: Seal all external cracks, joints, penetrations, edges, and entry points with appropriate caulking. Install rodent- and corrosion-proof screens (e.g., copper or stainless steel mesh) on all openings greater than ¼ inch (6 millimeters), except where code prohibits their installation (e.g., dryer vents), and measure: Design discharge points for rain gutters, air-conditioning condensation lines, steam vent lines, or any other moisture source such that discharge is at least 24 inches (600 millimeters) from the foundation.
In addition, project teams are eligible for an Innovation credit for additional moisture control items covered in Indoor airPLUS and not directly awarded in LEEDv4
Campus Applicable
No
Internationally Applicable:
No
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Case 1. Single Family
Meet all of the following requirements for local exhaust and outdoor air ventilation including the requirements of ASHRAE 62.2 – 2010, sections 4, 5 and 7 and Section 1503.4 of the 2009 International Residential Code (IRC), including:- Local Exhaust. Meet all the following requirements: Design and install local exhaust systems in all bathrooms (including half-baths) and the kitchen to meet the requirements of ASHRAE Standard 62.2–2010, Sections 5 and 7 or local equivalent, whichever is more stringent. Sample requirements that relate to minimum intermittent local exhaust flow rates are shown in Table 1. Exhaust air to the outdoors. Do not route exhaust ducts to terminate in attics or interstitial spaces. Recirculating range hoods or recirculating over-the-range microwaves do not satisfy the kitchen exhaust requirements. Use ENERGY STAR–labeled bathroom exhaust fans in all bathrooms (including half-baths) or performance equivalent for projects outside the U.S. A HRV or ERV can be used to exhaust single or multiple bathrooms if it has an efficacy level meeting the ENERGY STAR Technical Specifications for Residential Heat-Recovery Ventilators and Energy-Recovery Ventilators (H/ERVs) Version 2.0 as certified by HVI. For exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (188 liters per second), provide makeup air at a rate approximately equal to the exhaust air rate. Makeup air systems must have a means of closure and be automatically controlled to start and operate simultaneously with the exhaust system.
- Whole House Mechanical Ventilation. Design and install a whole-house mechanical ventilation system that complies with ASHRAE Standard 62.2–2010, Sections 4 and 7 or local equivalent, whichever is more stringent. Whole house ventilation fans must be rated for sound at a maximum of 1.0 sone per ASHRAE 62.2–2010, Section 7.2.1. Remote mounted fans need not meet these sound requirements.
The ASHRAE options can be summarized as follows:
- Continuous ventilation. Meet the ventilation requirements. Simplified minimum air-flow requirements are shown in Table 2.
- Intermittent ventilation. Use ASHRAE Standard 62.2–2010, Equation 4.2, to demonstrate adequate ventilation air flow.
- Any passive ventilation system must be approved and verified by a licensed HVAC engineer as providing ventilation equivalent to that achieved by continuous ventilation systems.
Table 1. Minimum air-flow requirements for intermittent local exhaust
|
Minimum air flow |
|---|---|
Kitchen |
100 cfm (47 liters per second); vented range hood required if continuous exhaust fan flow rate is less than 5 kitchen air changes per hour |
Bathroom, half-bath |
50 cfm (23 liters per second) |
Table 2a. Simplified minimum air-flow requirements (cfm) for continuous ventilation systems
Conditioned floor area (ft2) |
Bedrooms |
||||
|---|---|---|---|---|---|
0, 1 |
2, 3 |
4, 5 |
6, 7 |
> 7 |
|
≤ 1,500 |
30 |
45 |
60 |
75 |
90 |
1,501–3,000 |
45 |
60 |
75 |
90 |
105 |
3,001–4,500 |
60 |
75 |
90 |
105 |
120 |
4,501–6,000 |
75 |
90 |
105 |
120 |
135 |
6,001–7,500 |
90 |
105 |
120 |
135 |
150 |
> 7,500 |
105 |
120 |
135 |
150 |
165 |
Table 2b. Simplified minimum air-flow requirements (liters per second) for continuous ventilation systems
Conditioned floor area (m2) |
Bedrooms |
||||
|---|---|---|---|---|---|
0, 1 |
2, 3 |
4, 5 |
6, 7 |
> 7 |
|
≤ 139 |
14 |
21 |
28 |
35 |
42 |
140 – 279 |
21 |
28 |
35 |
42 |
49 |
280 – 418 |
28 |
35 |
42 |
49 |
56 |
419 – 557 |
35 |
42 |
49 |
56 |
63 |
558 – 697 |
42 |
49 |
56 |
63 |
70 |
> 698 |
49 |
56 |
63 |
70 |
77 |
Case 2. Multifamily
Design and install a whole-unit ventilation system for each individual dwelling unit that complies with the requirements of ASHRAE Standard 62.2–2010 (with errata) or local equivalent, whichever is more stringent, and all local exhaust requirements for Single Family section, above. Major components of the standard are summarized below.- Provide outdoor air to each unit directly from the outdoors. Project teams using exhaust ventilation systems must specify how outside air is delivered at the flow rate required by ASHRAE 62.2–2010. Do not use systems that rely on transfer air from pressurized hallways or corridors, adjacent dwelling units, attics, etc.
- For continuous ventilation systems, meet the requirements of ASHRAE 62.2–2010 shown in Table 2, Continuous in-unit ventilation fans must be rated for sound at a maximum of 1.0 sone, per ASHRAE 62.2–2010, Section 7.2.1. Remote mounted fans need not meet these sound requirements.
- For intermittent ventilation systems, install fans to meet ASHRAE Standard 62.2–2010. The fan flow rate must be equal to the outdoor air flow requirements multiplied by the fan flow rate multiplier. The system must be designed such that it can operate automatically based on a timer. Fans must be rated for sound at a maximum of 1.0 sone. Remote mounted fans need not meet these sound requirements.
- As applicable, follow the restrictions on system types for hot, humid climates and very cold climates. In hot, humid climates, whole-house mechanical net exhaust flow must not exceed 7.5 cfm per 100 square feet (38 liters per second per 100 square meters) of conditioned floor area. In very cold climates, mechanical supply-only systems must not exceed 7.5 cfm per 100 square feet (38 liters per second per 100 square meters). See ASHRAE 62.2–2010, Sections 4.5 and 8, for more details and climate categories.
- Locate air inlets that are part of the ventilation design at least 10 feet (3 meters) from known sources of contamination, such as a stack, vent, exhaust hood, or vehicle exhaust. Place the intake such that entering air is not obstructed by snow, plantings, or other material. Forced air inlets must be covered by screens to exclude rodents and insects (mesh not larger than ½ inch or 13 millimeters). See ASHRAE 62.2–2010, Section 6.8, for more details and a list of exceptions.
