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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Prerequisites
4.1 Basic outdoor air ventilation. Design and install a whole building ventilation system that complies with ASHRAE Standard 62.2-2007. A summary of alternatives is provided below, but the HVAC contractor should review and follow the requirements of ASHRAE Standard 62.2-2007, Sections 4 and 7.- Mild climate exemption. A home built in a climate with fewer than 4,500 infiltration degree-days3 is exempt from this prerequisite.
- Continuous ventilation. Meet the ventilation requirements in Table 1 below.
- Intermittent ventilation. Use Equation 4.2 of ASHRAE Standard 62.2-2007 to demonstrate adequate ventilation air flow.
- Passive ventilation. Have a passive ventilation system approved and verified by a licensed HVAC engineer as providing ventilation equivalent to that achieved by continuous ventilation systems as described in Table 1.
Credits
4.2 Enhanced outdoor air ventilation (2 points). Meet one of the following:a. In mild climates (fewer than 4,500 infiltration degree-days), install a whole-building active ventilation system that complies with ASHRAE Standard 62.2-2007.OR
b. Install a system that provides heat transfer between the incoming outdoor air stream and the exhaust air stream, such as a heat-recovery ventilator (HRV) or energy-recovery ventilator (ERV). The heat recovery system must be listed by a certified testing lab (e.g., UL, ETL).4.3 Third-party performance testing (1 point). Have a third-party test the flow rate of air brought into the home, and verify that the requirements of ASHRAE Standard 62.2-2007 are met. In exhaust-only ventilation systems, install exhaust ducts according to Table 7.1 of ASHRAE Standard 62.2-2007, and either test the flow rate out of the home or conduct air flow tests to ensure back-pressure of ≤ 0.20 inches w.c.Table 1 Minimum Air Flow Requirements for Continuous Ventilation Systems, in cfm
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 |
What does it cost?
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 »Documentation toolkit
The motherlode of cheat sheets
LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Prerequisites
4.1 Basic outdoor air ventilation. Design and install a whole building ventilation system that complies with ASHRAE Standard 62.2-2007. A summary of alternatives is provided below, but the HVAC contractor should review and follow the requirements of ASHRAE Standard 62.2-2007, Sections 4 and 7.- Mild climate exemption. A home built in a climate with fewer than 4,500 infiltration degree-days3 is exempt from this prerequisite.
- Continuous ventilation. Meet the ventilation requirements in Table 1 below.
- Intermittent ventilation. Use Equation 4.2 of ASHRAE Standard 62.2-2007 to demonstrate adequate ventilation air flow.
- Passive ventilation. Have a passive ventilation system approved and verified by a licensed HVAC engineer as providing ventilation equivalent to that achieved by continuous ventilation systems as described in Table 1.
Credits
4.2 Enhanced outdoor air ventilation (2 points). Meet one of the following:a. In mild climates (fewer than 4,500 infiltration degree-days), install a whole-building active ventilation system that complies with ASHRAE Standard 62.2-2007.OR
b. Install a system that provides heat transfer between the incoming outdoor air stream and the exhaust air stream, such as a heat-recovery ventilator (HRV) or energy-recovery ventilator (ERV). The heat recovery system must be listed by a certified testing lab (e.g., UL, ETL).4.3 Third-party performance testing (1 point). Have a third-party test the flow rate of air brought into the home, and verify that the requirements of ASHRAE Standard 62.2-2007 are met. In exhaust-only ventilation systems, install exhaust ducts according to Table 7.1 of ASHRAE Standard 62.2-2007, and either test the flow rate out of the home or conduct air flow tests to ensure back-pressure of ≤ 0.20 inches w.c.Table 1 Minimum Air Flow Requirements for Continuous Ventilation Systems, in cfm
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 |
