Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "Reference Guide Correction" "100000554" "2009-10-27" "Homes" "EAc6 - Space heating and cooling equipment" "None" "None" "Homes, 2008 edition" "201" "Note, under ""Requirements""" """Homes built without air-conditioning should be modeled under EA 1, using the default... and the rated homes."" change to ""Homes built either without air-conditioning or without heating should be modeled under EA 1, using the default... and the rated homes.""" "Reference Guide Correction" "100000555" "2009-10-27" "Homes" "EAc6 - Space heating and cooling equipment" "None" "None" "Homes, 2008 edition" "201" "Prereq 6.1 c)" """Install ENERGY STAR labeled programmable thermostat (except heat pumps and hydronic systems) change to ""Install programmable thermostat (except heat pumps and hydronic systems)" "Reference Guide Correction" "100000556" "2009-10-27" "Homes" "EAc6 - Space heating and cooling equipment" "None" "None" "Homes, 2008 edition" "203" "Column 1" "[Add new paragraph to beginning of Approach and Implementation section]\n""EA 6 only applies to projects with both heating and cooling. Homes built without air conditioning or without heating must be modeled and meet the requirements of EA 1.1.""\n" "Reference Guide Correction" "100000557" "2009-10-27" "Homes" "EAc6 - Space heating and cooling equipment" "None" "None" "Homes, 2008 edition" "204" "Verification and Submittals, 1st column" """Visually verify that all HVAC design calculations are completed."" change to ""Visually verify that all HVAC design calculations are completed per the Verification and Submittal Guidelines.""" "Reference Guide Correction" "100000558" "2009-10-27" "Homes" "EAc6 - Space heating and cooling equipment" "None" "None" "Homes, 2008 edition" "204" "Exemplary Performance" """No additional points are available for exemplary performance."" change to ""No additional points are available for exemplary performance. Projects that exceed the credit requirements are encouraged to use the performance pathway in EA 1.2.""" "LEED Interpretation" "1660" "2007-01-05" "Homes" "EAc6 - Space heating and cooling equipment" "Can baseboard electric systems use the prescriptive pathway? If so, what is the requirement for EA 6.1?" "No - homes with baseboard electric heating systems must use the performance pathway in EA 1." "None" "None" "LEED Interpretation" "1670" "2006-05-16" "Homes" "EAc6 - Space heating and cooling equipment" "The HVAC system is dual-stage. Is it okay if the air flow rate is > 15% higher than the design when at the high stage?" "For dual-stage furnaces, the system must meet the air flow requirements at the stage (high or low) for which the system was sized. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1706" "2007-03-08" "Homes" "EAc6 - Space heating and cooling equipment" "Is testing to be done with interior doors open or closed?" "Doors should be closed during room air flow testing. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1707" "2007-03-08" "Homes" "EAc6 - Space heating and cooling equipment" "Would like to confirm that the third-party flow testing may not be done by the HVAC installer or anyone from that company. Likewise, it cannot be completed by the builder or anyone from that company. So the flow testing may be performed by anyone not working within the builder or HVAC company, but it may be completed by the rater who is hired directly by the builder to do LEED for Homes testing and verification. If the above is confirmed, we would recommend spelling it out in the guidelines." "For now, tests must be done either by the rater or with a rater present. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1723" "2007-03-12" "Homes" "EAc6 - Space heating and cooling equipment" "What are the requirements for equipment that uses diesel?" "Diesel equipment must meet the same requirements as oil boilers or furnaces. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1813" "2007-06-12" "Homes" "EAc6 - Space heating and cooling equipment" "The efficiency of a ground-source heat pumps varies depending on the ground or water temperature. How should the efficiency (EER) of a ground-source heat pump be determined - based on the mean temperature below frost line, bin-weather analysis, or some other method?" "Credit for EA 6 must be based on the rated efficiency (EER or COP ) as determined using the standard test conditions set by the Air Conditioning and Refrigeration Institute. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1814" "2007-06-12" "Homes" "EAc6 - Space heating and cooling equipment" "The rating system describes doing Manual D and Manual J calculations. A full, by-the-book Manual D approach is almost unheard of in residential construction and most homes would fail it if this is the requirement. My read on it is that room-by-room Manual J calculations are required and a Manual D type approach is recommended. Is this correct? A Manual D calc requires a lot of data for blower fan curves, filter and coil pressure drops, detailed duct layout with all fittings specifically identified, etc." "The focus of this credit is for HVAC contractors to use an established method to design the distribution system. A very detailed Manual D calculation is not required (although recommended). " "None" "None" "LEED Interpretation" "1908" "2007-09-19" "Homes" "EAc6 - Space heating and cooling equipment" "Will LEED for Homes accept the Trane \'Ductulator\' as a computation procedure for IEQ 6.1? The Ductulator sizing method is based off the same ASHRAE Standard as the sizing calculations used for Manual D." "The Trane-Ductulator is a useful tool, but it will only calculate the pressure drop for a particular flow in a particular piece of ductwork. It cannot provide load calculations to determine how much air flow is needed in each room based on the air handler unit and the home design. These calculations are necessary, so the Ductulator alone is insufficient to meet the prerequisite. Please see the ACCA example worksheet http://www.acca.org/tech/codes/Manual_D_verification.pdf " "None" "None" "LEED Interpretation" "2003" "2007-12-10" "Homes" "EAc6 - Space heating and cooling equipment" "Does part (b) include the requirement that homes with heat pumps include programmable thermostats have adaptive recovery?" "Yes, homes that have a heat pump must have a programmable thermostat with adaptive recovery. " "None" "None" "LEED Interpretation" "2004" "2008-01-17" "Homes" "EAc6 - Space heating and cooling equipment" "EQ 6.2 gives 1 point for flow control valves on every radiator, but EQ 6.3 gives 2 points for having 2 or more distinct zones with independent thermostat controls. What does this mean, and why does it receive more points than the flow control valves? " "EQ 6.3 now is granted for having 2 or more distinct zones with independent thermostatic controls. Independent zones must include separate loops and separate pumps controlled automatically by a thermostat control. Simply having flow control valves on each radiator does not constitute separate zones. It is easy and good practice to enable manual room-by-room occupant control of temperature, though, which is why it is awarded 1 point. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2267" "2008-07-21" "Homes" "EAc6 - Space heating and cooling equipment" "For part (a), if a multi-family project conducts the Manual J calculation and estimates that the proper HVAC size is smaller than any commercially available unit (1.5 tons), how should the prerequisite be met?" "If the Manual J calculations indicates the need for an HVAC unit that is smaller than any commercially available unit, it is acceptable to put in a slightly oversized unit." "None" "None" "LEED Interpretation" "2269" "2008-07-21" "Homes" "EAc6 - Space heating and cooling equipment" "For part (a), can a Manual N calculation (common for commercial projects) be used in multifamily projects instead of Manual J?" """The requirement allows """"an equivalent computation procedure"""". The burden of proof lies with the project team to demonstrate to the Green Rater and Provider’s satisfaction that a methodology is considered """"equivalent"""". Here are a few guidelines: \n • Any sizing approach should include inputs that are based on the specifics of the home, such as solar gains from windows, duct losses, envelope leakage and insulation levels, etc. • Some tools are “powered by ACCA Manual J” and have a logo to indicate this. • If the Green Rater or Provider is uncertain, both approaches (the proposed approach and ACCA Manual J) should be used to determine equivalence."" " "None" "None" "LEED Interpretation" "2270" "2008-07-21" "Homes" "EAc6 - Space heating and cooling equipment" "For part (a), can the Carrier Hourly Analysis Program (Version 4.34) be used in multi-family projects instead of Manual J? This method conducts an hourly analysis of unit loading rather than the peak loading provided by a Manual J." "The requirement allows ""an equivalent computation procedure"". The burden of proof lies with the project team to demonstrate to the Green Rater and Provider\'s satisfaction that a methodology is considered ""equivalent"". Here are a few guidelines: \n" "None" "None" "LEED Interpretation" "2345" "2008-11-12" "Homes" "EAc6 - Space heating and cooling equipment" "For part (a), what is the maximum allowable oversizing? Does it differ depending on whether heating or cooling is the primary concern?" "LEED for Homes follows the guidance in the ENERGY STAR for Homes BOP: ""Maximum oversizing limit for air conditioners and heat pumps is 15% (with the exception of heat pumps in Climate Zones 5 - 8, where the maximum oversizing limit is 25%).""" "None" "None" "LEED Interpretation" "2571" "2009-06-13" "Homes" "EAc6 - Space heating and cooling equipment" "The most current version of Manual J is version 8. Is it acceptable to meet the requirements using Manual J, version 7?" "The use of Manual J, version 7 does meet the intent of the requirement. \n\nIn the future, the LEED for Homes Rating System will specify the version of the applicable standard or manual for each prerequisite and credit." "None" "None" "LEED Interpretation" "2572" "2009-06-13" "Homes" "EAc6 - Space heating and cooling equipment" "EQ 6.2 (a) requires ""Size the opening to 1 square inch per cfm of supply (this area may include free area undercut below door)"", and allows various strategies including returns, transfer grilles, or jump ducts. If a project has a return that is suited to the distribution system, but is smaller than 1 square inch per CFM, can it still earn the point?" "If a project installs returns that are ducted directly to the AHU in every room, and these returns are properly sized as per Manual D, then the intent of EQ 6.2 (a) has been met and the project may be awarded credit. This is true even if the size of the return is less than 1 square inch per CFM. " "None" "None" "LEED Interpretation" "2651" "2009-09-15" "Homes" "EAc6 - Space heating and cooling equipment" "EQ 6.1 states: ""(using ACCA Manuals J and D, the ASHRAE Handbook of Fundamentals, or an equivalent computation procedure)"" The project team intends to use the Carrier E20-II software to calculate loads. This software follows ASHRAE standards. Does this meet the intent of ""an equivalent computation procedure""?" "Green Rater has some discretion in determining this. The software needs to have the capability to produce room-by-room load calculations based on specific features of the home (e.g. location, green EE features) that can be used to properly size the HVAC equipment and distribution system." "None" "None" "LEED Interpretation" "2652" "2009-09-15" "Homes" "EAc6 - Space heating and cooling equipment" "EQ 6.1 requires ACCA Manual D or an equivalent. If a project installs a ductless system, such as a mini-split, is this requirement waived? " "A Manual D calculation is not required, but ductless projects still have to do calculations to determine the room-by-room loads based on specific features of the home and then calculations to determine how to size the distribution system to satisfy these loads. In the case where individual heating and cooling units are used in each room (e.g. radiant floor heating, mini-splits), the distribution requirement may be satisfied by performing the load calculations and then following manufacturer\'s guidance to meet these loads.\n" "None" "None" "LEED Interpretation" "2664" "2009-10-07" "Homes" "EAc6 - Space heating and cooling equipment" "The V&S Guidelines indicate that the Green Rater should verify ""calculation of total effective length (TEL) for the longest supply and return duct run."" What if the TEL is embedded within the software, or the HVAC contractor uses a different method for calculating friction or pressure drop across the ductwork?" "If the TEL cannot be verified, it\'s acceptable to verify an equivalent calculation for the friction coeffecient or pressure drop over the ductwork. TEL is one way to estimate pressure drop over ductwork, but there are other methods. " "None" "None" "LEED Interpretation" "2692" "2009-10-31" "Homes" "EAc6 - Space heating and cooling equipment" "Is there a requirement that the compressor and coil (indoor and outdoor coils) be matched? If not, how should the system efficiency be determined?" "LEED for Homes follows the guidance in the Energy Star for Homes BOP: ""Indoor and outdoor coils shall be matched in accordance with ARI standards."" All split systems must meet this requirement, and there must be an AHRI rating for the system being installed." "None" "None" "LEED Interpretation" "2744" "2009-12-29" "Homes" "EAc6 - Space heating and cooling equipment" "Is a separate Manual D calculation required if the units have hydronic heating, and include flow control valves?" "A Manual D calculation is not required, but ductless projects still have to do calculations to determine the room-by-room loads based on specific features of the home and then calculations to determine how to size the distribution system to satisfy these loads. In the case where individual heating and cooling units are used in each room (e.g. radiant floor heating, mini-splits), the distribution requirement may be satisfied by performing the load calculations and then following manufacturer\'s guidance to meet these loads.\n" "None" "None" "LEED Interpretation" "2745" "2009-12-29" "Homes" "EAc6 - Space heating and cooling equipment" "Is a separate Manual J & D calculation required for each bedroom in each unit of a multi-family building?" "A Manual J (or equivalent calculation) is required for each unit in multi-family or multi-home projects. If multiple units have the same design (including size, orientation, exposure, and energy-efficiency measures), it may be possible to re-use the calculation." "10394, 10393" "None" "LEED Interpretation" "2753" "2010-01-04" "Homes" "EAc6 - Space heating and cooling equipment" "Can projects with mini-split systems earn EQ 6.3? What must be done to earn the credit? Should it be awarded automatically based on the requirements for nonducted systems, or should projects have to do testing?" "Projects with mini-split systems may earn this credit by meeting the requirement for nonducted systems: ""Install system with at least two distinct zones with independent thermostat controls.""" "None" "None" "LEED Interpretation" "3125" "2007-04-05" "Homes" "EAc6 - Space heating and cooling equipment" "FSEC has found that flow hoods have a lot of variability - up to 30%. How can they verify air flow within +/- 15% if the flow hood has a range of error of 30%? If you do testing multiple times you may eventually get the right number." "There is variability in flow hood measurements, depending on how it\'s used, which flow hood is used, when it\'s used, etc. This variability is acceptable, as the focus of this requirement is to find problems that take the air flow well outside the range of acceptability (e.g. due to crushed ducts, large leaks, etc.). It is a matter of professional judgment, but if a rater does a couple of tests and one of them is within the +/-15% threshold, that\'s acceptable. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5013" "2007-02-16" "Homes" "EAc6 - Space heating and cooling equipment" "How should dual-stage heat pumps or furnaces be rated for EA 6 if the performance specifications are different at the different stages?" "For dual-stage furnaces and heat pumps, a weighted efficiency should be calculated using detailed load calculations to estimate the percentage that the equipment will operate at each stage. In lieu of such calculations, a weighted average based on 70% at the low stage and 30% at the high stage can be used. \n\nEA credit 6 will also be changed to include a verification requirement for geothermal heat pumps to ensure that the pipe/well system is properly sized as per manufacturer\'s specs." "None" "None" "LEED Interpretation" "10394" "2014-07-01" "Homes, Mid-rise" "EAc6 - Space heating and cooling equipment" "When can load sizing calculations be reused on different units? " "Requiring every unique iteration of units to have a separate Manual J is burdensome, especially considering the small heating and cooling loads in many multifamily units, and large relative HVAC equipment size. Response: The HVAC designer can use their professional experience when performing load calculations on similar units. A unique Manual J (or equivalent calculation) must be performed on any unit that is expected to have a load difference of at least 25% from other units (based on different sizes or energy efficiency measures), or the next equipment size up, whichever is smaller. Separate calculations must be performed for each similarly sized group of units that have unique orientation and exposure. " "2745, 10393" "None" "X"