LEEDuser’s viewpoint
Explore this LEED credit
Post your questions on this credit in the forum, and click on the credit language tab to review to the LEED requirements.
Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
A. Forced-air systemsPrerequisites
5.1 Reduced distribution losses. Meet the following requirements:- Limit duct air leakage rate to outside the conditioned envelope. The tested duct leakage rate must be ≤ 4.0 cfm at 25 Pascals per 100 square feet of conditioned floor area (for each installed system), verified by the qualified energy rater. Testing is waived if the home meets EA 5.3 (b) or (c).
- Do not install ducts in exterior walls unless extra insulation is added to maintain the overall UA for an exterior wall without ducts. Ducts may be run inside interior wall cavities but must be fully ducted (i.e., do not use the wall cavity as the duct).
- Use at least R-6 insulation around ducts in unconditioned spaces.
Credits
5.2 Greatly reduced distribution losses (2 points). Limit duct air leakage to outside the conditioned envelope. The tested duct leakage rate must be ≤ 3.0 cfm at 25 Pascals per 100 square feet of conditioned floor area (for each installed system), verified by the qualified energy rater.OR
5.3 Minimal distribution losses (3 points). Meet one of the following requirements:a. Limit duct air leakage to outside the conditioned envelope. The tested duct leakage rate must be ≤ 1.0 cfm at 25 Pascals per 100 square feet of conditioned floor area, verified by the qualified energy rater.b. Locate the air-handler unit and all ductwork within the conditioned envelope and minimize envelope leakage (i.e., meet the requirements of EA 3.3).c. Locate the air-handler unit and all ductwork visibly within conditioned spaces (i.e., no ductwork hidden in walls, chases, floors, or ceilings).B. Nonducted HVAC systems (e.g., hydronic systems)Prerequisites
5.1 Reduced distribution losses. Use at least R-3 insulation around distribution pipes in unconditioned spaces.Credits
5.2 Greatly reduced distribution losses (2 points). Keep the system (including boiler and distribution pipes) entirely within the conditioned envelope.5.3 Minimal distribution losses (1 point). Install outdoor reset control (i.e., controls that modulate distribution water temperature based on outdoor air temperature). See all forum discussions about this credit »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
A. Forced-air systemsPrerequisites
5.1 Reduced distribution losses. Meet the following requirements:- Limit duct air leakage rate to outside the conditioned envelope. The tested duct leakage rate must be ≤ 4.0 cfm at 25 Pascals per 100 square feet of conditioned floor area (for each installed system), verified by the qualified energy rater. Testing is waived if the home meets EA 5.3 (b) or (c).
- Do not install ducts in exterior walls unless extra insulation is added to maintain the overall UA for an exterior wall without ducts. Ducts may be run inside interior wall cavities but must be fully ducted (i.e., do not use the wall cavity as the duct).
- Use at least R-6 insulation around ducts in unconditioned spaces.
Credits
5.2 Greatly reduced distribution losses (2 points). Limit duct air leakage to outside the conditioned envelope. The tested duct leakage rate must be ≤ 3.0 cfm at 25 Pascals per 100 square feet of conditioned floor area (for each installed system), verified by the qualified energy rater.OR
5.3 Minimal distribution losses (3 points). Meet one of the following requirements:a. Limit duct air leakage to outside the conditioned envelope. The tested duct leakage rate must be ≤ 1.0 cfm at 25 Pascals per 100 square feet of conditioned floor area, verified by the qualified energy rater.b. Locate the air-handler unit and all ductwork within the conditioned envelope and minimize envelope leakage (i.e., meet the requirements of EA 3.3).c. Locate the air-handler unit and all ductwork visibly within conditioned spaces (i.e., no ductwork hidden in walls, chases, floors, or ceilings).B. Nonducted HVAC systems (e.g., hydronic systems)