HERS verification is required only when certain regulated efficiency requirements or equipment features are installed. If such efficiency requirements or equipment features are not installed, then HERS verification is not required. For example, if a dwelling that must comply with the Energy Code does not have air distribution ducts, then HERS verification for duct leakage is not required for compliance.

The following features require HERS verification:

• Duct sealing
• Duct location, surface area, and R-value
• Low-leakage ducts entirely in conditioned space
• Low-leakage air handlers
• Verification of return duct design
• Verification of air filter device design, filter MERV rating, and labeling
• Verification of prescriptive bypass duct requirements
• Refrigerant charge in ducted split-system and ducted packaged unit air conditioners and heat pumps, and mini-split systems
• Refrigerant fault indicator display (FID)
• Verified system airflow
• Air handler fan efficacy
• Verified energy efficiency ratio (EER)
• Verified seasonal energy efficiency ratio (SEER)
• Heat pump-rated heating capacity
• Evaporatively cooled condensers
• Variable-capacity heat pump credit
• Whole-house fan
• Central fan ventilation cooling systems
• Continuous whole-building mechanical ventilation airflow
• Intermittent whole-building mechanical ventilation airflow
• Kitchen exhaust (including vented range hoods)
• Building envelope air leakage
• Quality insulation installation (QII)
• Quality insulation installation for spray polyurethane foam
• Verified pipe insulation credit (PIC-H)
• HRV/ERV system fan efficacy
• Verified central parallel piping (PP-H)
• Verified compact hot water distribution system expanded credit (CHWDS-H-EX)
• Demand recirculation: manual control (R-DRmc-H)
• Demand recirculation: sensor control (R-DRsc-H)
• Multiple recirculation loop design for DHW systems serving multiple dwelling units
• Verified drain water heat recovery system (DWHR-H)

At the builder’s option, HERS testing may be completed for each dwelling unit (100 percent testing) or for a group of dwelling units (sampling). Sampling for newly constructed units is permitted only when multiple dwelling units of similar design are constructed within the same subdivision by the same subcontractor. Sampling may also be used, at the builder’s or installer’s option, for alterations for groups composed of dwellings having the same requirements installed that require HERS testing, and where the same installing contractor has installed the requirements. More details are in Reference Residential Appendix Section RA2.6 and RA2.8.

To be included in a sample group, the builder or subcontractor must provide the HERS Rater with a copy of the registered CF1R and CF2R as specified in Reference Residential Appendix Section RA2.5. The building owner or installer must give the HERS Rater project access on the registry to facilitate planning and execution of sampling.

The installer must self-test every requirement and sign as the responsible person on the appropriate CF2Rs. The HERS Rater may test a representative home (referred to as the “model”) to help the installer identify any issues before self-testing the remaining homes. See Section 2.5.3.

Prior to performing any HERS verification, the HERS Rater must confirm that the CF1R and CF2Rs have been registered for each dwelling unit to be tested. It is the HERS Rater that facilitates dwelling unit grouping without direction from the installer or builder. The HERS Rater also chooses the first of each type of HERS requirement to test without any forewarning.

The HERS Rater will transmit all test results to the registry and sign as the responsible person on the CF3Rs. The HERS provider will make available a registered copy of the completed and signed CF3Rs to all approved authorized users of the registry. Printed copies, electronic or scanned copies, and photocopies of the registered CF3Rs will be allowed for document submittals, subject to authentication between the copy and the registered certificate. A registered copy of the CF3R must be posted at the building site or made available for review by the enforcement agency in conjunction with requests for final inspection for each dwelling unit.

The HERS provider will make available, via phone or Internet, a way for authorized users of the HERS registry to verify that the information displayed on copies of registered documents on file in the registry for the dwelling unit.

If the builder chooses the sampling option, the procedures in Reference Residential Appendix Sections RA2.6 and RA2.8 must be followed.

The HERS Rater must perform the required HERS verification on the first dwelling unit of each model within a subdivision. To be considered the same model, dwelling units must have the same basic floor plan layout, energy design, and compliance features as shown on the CF1Rs. Variations in the basic floor plan layout, energy design, compliance features, zone floor area, or zone volume that do not change the features to be verified, the heating or cooling capacity of the HVAC unit(s), or the number of HVAC units specified for the dwelling units will not cause dwelling units to be considered a different model.

The initial model HERS verification allows the builder to identify and correct any potential construction flaws or practices in the build-out of each model. If HERS verification determines that the requirements for compliance are met, the HERS Rater will transmit the HERS verification results to the HERS registry.

After the initial model HERS verifications are completed, the builder or the builder’s authorized representative determines which sampling procedure is to be used for the group of dwellings that require HERS testing. There are two procedures for HERS testing using group sampling: (1) sampling a closed group of up to seven dwellings and (2) sampling of an open group of up to five dwellings. The group sampling requirements for each procedure will be discussed in this section. If available, a TPQCP allows up to 30 dwelling units to be grouped.

Transmittal/submittal of the CF2R information, for at least one dwelling, to the HERS registry is required to open a new group. Additional dwellings may be entered into the registry and included in an “open” group over a specific period, subject to transmittal/submittal of the CF2R to the registry for each additional dwelling. However, the group shall not remain open to receive additional dwellings for a period longer than six months from the earliest date shown on any CF2R for a dwelling included in a group. A group may be closed at any time after the group has been opened at the option of the builder or builder’s authorized representative. The size of a closed group may range from a minimum of one dwelling to a maximum of seven dwellings. When a group is closed, no additional dwellings shall be added to the group.

1. Sampling of a closed group of up to seven dwellings requires the following conditions to be met as prerequisite to receiving CF3R for the group:
   1. All the dwelling units in the sample group have been identified. Up to seven dwellings are allowed to be included in a closed sample group.
   2. Installation and diagnostic testing of all the features that require HERS verification have been completed by the installer in all dwellings in the group, and all CF2Rs are registered.
   3. The group has been classified as a closed group in the data registry.
   4. At the request of the builder or the builder’s authorized representative, a HERS Rater will randomly select one dwelling unit from the closed sample group to begin HERS verification. If the dwelling unit meets the compliance requirements, this tested dwelling and each of the other nontested dwellings in the group will receive a registered certificate of verification. Alternatively, the rater may test and verify requirements in different dwelling units in the group.
2. Sampling of an open group of up to five dwellings requires the following conditions to be met as prerequisite HERS verification on the group:
   1. At least one dwelling unit from the sample group has been identified. Up to five dwellings are allowed to be included in an open sample group.
   2. Installation of all the features that require HERS testing shall be completed by the installer in all dwellings. Registration of the CF2Rs for all the dwellings has been completed.
   3. At the request of the builder or the builder’s authorized representative, a HERS Rater will randomly select one dwelling unit from the open sample group for HERS verification. If the dwelling unit meets the compliance requirements, the tested dwelling and each of the other nontested dwellings shall receive a registered CF3R. If there are fewer than five dwelling units, the group shall be allowed to remain open and eligible to receive additional dwelling units. Dwelling units entered into the open group after the successful CF3R of the tested dwelling shall also receive a registered CF3R as a nontested dwelling subject to receipt of the registered CF2R by the HERS registry for the dwelling. The group shall be closed when it reaches the limit of five dwellings, when the six-month limit for open groups has been exceeded, or when the builder requests that the group be closed.

The HERS Rater must confirm that the CF2Rs have been registered and are consistent with the CF1R for the dwelling unit.

The HERS Rater must perform one or more HERS verification on the selected dwelling unit and enter the results into the HERS registry regardless of whether the results indicate a pass or fail. If the test fails, then the failure must be entered into the registry, even if the installer immediately corrects the problem. In addition, any applicable procedures for resampling, full testing, and corrective action must be followed as described in Section 2.5.5 below.

If HERS verification determines that the requirements for compliance are met, the HERS Rater will enter the test results into the HERS registry. The HERS provider will make available to approved users of the registry a registered copy of the CF3R for the tested requirement and for all other nontested requirements in the group at the time of the sample test. To avoid confusion by placing test results on untested requirements, the registry will not report the results of tested requirements on the corresponding CF3Rs for untested requirements in the sample group. The results will be reported only on the CF3R for the tested requirements within the sample group. However, CF3Rs for untested features will conform to all other registration requirements and specify that the feature was not tested but has passed compliance as part of a sample group. The HERS provider must close any open group within six months after the earliest signature date shown on any CF2R for a dwelling entered in the group. When such group closure occurs, the provider shall notify the builder that the group has been closed and require that a sample dwelling be selected for HERS verification by a HERS rater if HERS verification has not yet been conducted on a sample dwelling entered in the group.

When a failure is encountered during sample testing, the failure must be entered into the HERS registry for retention by the HERS Rater. Corrective action must be taken on the failed dwelling unit. The dwelling unit must be retested to verify that corrective action was successful, and the dwelling complies. Corrective action and retesting on the dwelling unit must be repeated (and registered) until the testing determines that the dwelling complies, and the successful compliance results have been entered into the registry. A registered CF3R for the dwelling shall be made available to authorized users of the registry.

In addition, the HERS Rater must resample and test a second randomly selected dwelling within the sample group to assess whether the first failure is unique or if the rest of the dwelling units are likely to have similar failings. “Resampling” is the procedure that requires testing of additional dwellings within a group when the initial selected sample dwelling from a group fails to pass HERS verification.

When resampling in a closed group, if the testing of a second randomly selected dwelling in the group confirms that the requirements for compliance credit are met for that unit, then the unit with the initial failure does not indicate failure in the remaining untested units. A copy of the CF3R will be made available for the remaining dwelling units in the group, including the unit in the resample. If the second sample results in a failure, the HERS Rater must report the second failure to the registry. All the nontested units in the group must be individually HERS-verified.

Additional information is in Reference Residential Appendix RA2.6.

When compliance for an alteration requires HERS verification by a certified HERS Rater, the building owner may choose for the HERS verification to be completed for each dwelling unit or as part of a designated sample group of dwelling units. The building own may choose the same installing company that completed the work that requires HERS verification for compliance. The dwelling units in a designated sample group are not required to be within the same enforcement agency jurisdiction; however, a enforcement agency may require that a separate dwelling unit from the sample group that is located within its jurisdiction be tested. The only alterations that will require HERS verification are HVAC changeouts. When compliance requires HERS verification, the building owner or its agent must arrange for registration of the CF1R information to the registry, identifying the altered HVAC system and features that require HERS verification. The building owner must also submit an registered copy of the CF1R to the HERS Rater.

When the installation is complete, the person responsible for the performance of the installation must complete the CF2Rs. If the HERS Rater tests the features on behalf of the installer, this test disqualifies the associated dwelling from group sampling, and the dwelling must be removed from the group or else all dwellings in that group must be verified.

After confirming that the CF1R and all required CF2Rs are registered, the HERS Rater must perform the HERS verification for each HERS requirement. The sampling procedures described in Reference Residential Appendix RA2.6.3.3 and RA2.8 for sampling a closed group of up to seven dwellings must be used. It requires that all dwelling units (HVAC systems) within the group have been serviced by the same installing company. The installing company may request a group for sampling that is smaller than seven dwelling units (HVAC systems). Resampling, full testing, and corrective action must be completed, if necessary, as specified by Reference Residential Appendix RA2.6.4.

Whenever the HERS Rater for the group is changed, a new group must be established.

The enforcement agency(ies) cannot approve the alteration until the agency has a registered CF1R, CF2R, and CF3R for the altered HVAC system. The agency will also verify that the installing contractor provides copies of all these forms to the homeowner .

TPQCP, as specified in Reference Residential Appendix RA2.7, may also be used with alterations and must be limited to closed sample group sizes of 30 dwelling units or fewer. When a TPQCP is used, the enforcement agency may approve compliance based on the CF2Rs where data checking has indicated that the unit complies, on the condition that if the required HERS testing procedures determine that resampling, full testing, or corrective action is necessary, such work shall be completed.

More details on HERS verification and HERS registries are in the 2022 Reference Residential Appendices and 2022 Reference Joint Appendices, as described below:

1. Reference Joint Appendix JA7 – Data Registry Requirements
2. Reference Residential Appendix RA2 – Residential HERS Verification, Testing, and Documentation Procedures
3. Reference Residential Appendix RA3 – Residential Field Verification and Diagnostic Test Protocols

Example 2-9

Question

Given a multifamily building that has ducted HVAC systems and HERS-verified duct leakage verification for all the dwelling units in the building, what is the correct sampling procedure for HERS field verification and diagnostic testing for the air distribution ducts?

Answer

If the builder of a multifamily building chooses to comply using sampling, then the sampling is done using groups composed of dwelling units that have used the same HERS requirements for compliance but also share the same basic floor plan layout and energy design. (These similar features define the model.) Dwellings that do not have the same HERS requirements specified for compliance are not allowed to be placed in the same HERS sample group.

For multifamily buildings, variations in exterior surface areas caused by location of dwelling units within the building do not cause dwelling units to be considered a different model floor plan. When verifying a dwelling unit, all the duct systems associated with every HVAC unit in the dwelling must be tested to determine compliance for that dwelling.

For this example, since duct testing is the only HERS requirement specified for all the dwelling units, all the dwelling units in the building can be grouped together for HERS verification requirements. The procedures for assigning dwellings to groups and the HERS verification of a sample from each group must follow the same procedure as for single- family dwellings described in Section 2.5.2 in this chapter and in Reference Residential Appendix RA2.

The installer will designate a dwelling unit for each model in the building to be verified by the rater before the formation of sample groups.

After verification of the first dwelling of each model floor plan is complete, the rater must randomly select a sample dwelling unit from each group of dwellings that have been formed. These samples must be tested according to applicable procedures in Reference Residential Appendix RA3 and documented according to procedures in Reference Residential Appendix RA2. In a sampled dwelling unit that is to be tested to confirm compliance, the duct system associated with every HVAC unit in that dwelling unit must be tested. However, duct systems do not have to be tested in dwelling units that are not selected for sampling (nontested dwelling), provided the dwelling that was tested complies.

If the tested dwelling in the group complies with the verification, the remaining dwellings in the sample group are certified for compliance based on the results of the sample dwelling test result. Testing must be done on every duct system in a dwelling unit, regardless of whether it appears that the HVAC and duct system are in conditioned space. This is akin to a single-family residence with one HVAC unit serving upstairs with ducts in the attic and another serving downstairs with ducts between floors.