## 2.5 HERS Field Verification and Diagnostic Testing

This section describes some procedures and requirements for field verification and/or diagnostic testing of energy efficiency features.

Field verification and diagnostic testing are performed by special third-party inspectors called HERS Raters. The Energy Commission has given this responsibility to the raters, who must be specially trained and certified to perform these services. The raters cannot be employees of the builder or contractor whose work they are verifying. Also they cannot have a financial interest in the builder’s or contractor’s business, or advocate or recommend the use of any product or service that they are verifying. The training, quality assurance, and general oversight of the raters are conducted by Energy Commission-approved HERS Providers.

### 2.5.1 Measures Requiring HERS Field Verification and Diagnostic Testing

Field verification and diagnostic testing are required only when certain regulated efficiency measures or equipment features are installed. If such efficiency measures or equipment features are not installed, then field verification and diagnostic testing are not required. For example, if a dwelling that must comply with the standards does not have air distribution ducts, then HERS verification of duct leakage is not required for compliance.

The following features require field verification and/or diagnostic testing:

a. Duct sealing

b. Supply duct location, surface area and R-value

c. Low-leakage ducts in conditioned space

d. Low-leakage air handlers

e. Verification of return duct design

f. Verification of air filter device design, filter MERV rating, and labeling

g. Verification of bypass duct prohibition

h. Refrigerant charge in ducted split-system and ducted packaged unit air conditioners and heat pumps, and mini-split systems

i. Refrigerant fault indicator display (FID)

j. Verified system airflow

k. Air handler fan efficacy

l. Verified energy efficiency ratio (EER)

m. Verified seasonal energy efficiency ratio (SEER)

n. Heat Pump Rated Heating Capacity

o. Maximum rated total cooling capacity

p. Evaporatively-cooled condensers

q. Ice storage air conditioners

r. Continuous whole-building mechanical ventilation airflow

s. Intermittent whole-building mechanical ventilation airflow

t. Building envelope air leakage

u. High-quality insulation installation (QII)

v. Quality insulation installation for spray polyurethane foam

w. PV field verification protocol

x. Kitchen hood HVI listing for airflow and noise (sones)

y. Verified parallel piping

z. Central fan integrated ventilation cooling systems

aa. Whole house fan

bb. Zonal controls

cc. Verified compact hot water distribution system

dd. Verified pipe insulation credit

ee. Verified drain water heat recovery system

ff. Verified point of use

gg. Demand recirculation: manual control

hh. Demand recirculation: sensor control

ii. Multiple recirculation loop design for DHW systems serving multiple dwelling units

### 2.5.2 Verification, Testing and Sampling

At the builder’s option, HERS field verification and diagnostic testing may be completed for each dwelling unit or for a sample of dwelling units. Sampling is permitted only when multiple dwelling units of the same type are constructed within the same subdivision by the same subcontractor. Sampling may also be used for alterations for groups composed of dwellings having the same measure installed that requires HERS verification, and where the same installing contractor has installed the measures. More details are in Reference Residential Appendix Section RA2.6 and RA2.8.

The builder or subcontractor must provide to the rater a copy of the certificate of compliance approved/signed by the principal designer/owner and a copy of the certificate(s) of installation signed/certified by the builder or subcontractors as specified in Reference Residential Appendix Section RA2.5.

When compliance requires document registration, prior to performing field verification and diagnostic testing, the rater must verify that transmittal to the data registry of the (CF1R) and (CF2R) information has been completed for each dwelling unit for which compliance requires HERS verification.

For all HERS verification procedures, the rater must confirm that the certificate(s) of installation have been completed as required, and that all other information show compliance consistent with the requirements given in the plans and specifications and certificate of compliance approved by the local enforcement agency.

If field verification and diagnostic testing determines that the requirements for compliance are met, the HERS Rater shall transmit the test results and certification/signature to the data registry. The provider shall make available a registered copy of the completed and signed certificate of verification to the rater, the builder, the enforcement agency, and other approved users of the HERS registry. Printed copies, electronic or scanned copies, and photocopies of the completed, signed and registered certificate of verification shall be allowed for document submittals, subject to verification that the information contained on the copy conforms to the registered document information currently on file in the data registry. A completed, signed and registered copy of the certificate of verification 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 shall make available via phone or Internet a way for building officials, builders, HERS Raters, and other authorized users of the data registry to verify that the information displayed on copies of the submitted certificate(s) conforms to the registered document information 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.

### 2.5.3 Initial Model Field Verification and Diagnostic Testing

The HERS Rater must diagnostically test and field verify the first dwelling unit of each model within a subdivision or multifamily housing development. 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 certificate of compliance for each dwelling unit. Variations in the basic floor plan layout, energy design, compliance features, zone floor area, or zone volume, that do not change the HERS features to be tested, the heating or cooling capacity of the HVAC unit(s), or the number of HVAC units specified for the dwelling units, shall not cause dwelling units to be considered a different model. For multifamily buildings, variations in exterior surface areas caused by location of dwelling units within the building shall not cause dwelling units to be considered a different model.

The initial model testing allows the builder to identify and correct any potential construction flaws or practices in the build out of each model. If field verification and diagnostic testing determines that the requirements for compliance are met, the HERS Rater will transmit the test results to the data registry. The provider will make available a registered copy of the certificate of verification to the rater, the builder, the enforcement agency, and other authorized users of the data registry.

### 2.5.4 Group Sample Field Verification and Diagnostic Testing

After the initial model field verification and diagnostic testing 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 field verification. There are two procedures for HERS verification compliance using group sampling: (1) sampling of 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.

Transmittal/submittal of the certificate(s) of installation 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 certificate(s) of installation information 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 certificate of installation 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.

A. Sampling of a closed group of up to seven dwellings requires the following conditions to be met as prerequisite to receiving HERS compliance verification 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 of all the measures that require HERS verification has been completed in all the dwellings in the group, and registration of the certificate(s) of installation for all the dwellings has been completed.

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 rater will randomly select one dwelling unit from the closed sample group for field verification and diagnostic testing. 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.

B. Sampling of an open group of up to five dwellings requires the following conditions to be met as prerequisite to receiving HERS compliance verification for 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 measures that require HERS verification shall be completed in all the dwellings. Registration of the certificate(s) of installation for all the dwellings has been completed.

3. At the request of the builder, or the builder’s authorized representative, a rater will randomly select one dwelling unit from the open sample group for field verification and diagnostic testing. If the dwelling unit meets the compliance requirements, the tested dwelling and each of the other nontested dwellings shall receive a registered certificate of verification. 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 HERS compliance verification of the tested dwelling shall also receive a registered certificate of verification as a nontested dwelling subject to receipt of the registered certificate(s) of installation by the data 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 rater must confirm that the certificate(s) of installation have been completed as required, and that the installer’s diagnostic test results and the certificate(s) of installation show compliance consistent with the certificate of compliance for the dwelling unit.

The rater must diagnostically test and field verify the selected dwelling unit, and enter the test and/or field verification results into the data registry regardless of whether the results indicate a pass or fail. If the test fails, then the failure must be entered into the provider’s 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 field verification and diagnostic testing determine that the requirements for compliance are met, the HERS Rater will enter the test results into the data registry. The provider will make available to the rater, the builder, the enforcement agency, and other approved users of the data registry, a registered copy of the certificate of verification for the tested dwelling, and for all other nontested dwelling units in the group at the time of the sample test. In order not to create confusion by placing test results on nontested dwelling units, the data registry will not report the testing/verification results of the tested home on the certificate of field verification and diagnostic testing for nontested dwelling units in a sample group. The results will be reported only on the CF3R for the tested dwelling unit of the sample group. However, CF3R forms for nontested dwelling units will still have a registration number and date, and a watermark of the provider’s seal, and so forth and will specify the dwelling unit was not tested and is part of a sample group.

The provider must close any open group within six months after the earliest signature date shown on any certificate of installation 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 field verification and diagnostic testing by a rater if field verification has not yet been conducted on a sample dwelling entered in the group.

### 2.5.5 Resampling, Full Testing, and Corrective Action

When a failure is encountered during sample testing, the failure must be entered into the data registry for retention by the HERS Rater. Corrective action must then be taken on the failed dwelling unit, and the dwelling unit must subsequently be retested to verify that corrective action was successful and the dwelling complies. Corrective action and retesting on the dwelling unit must be repeated until the testing determines that the dwelling complies and the successful compliance results have been entered into the HERS registry. A registered certificate of verification for the dwelling shall be made available to the rater, the builder, the enforcement agency, and other authorized users of the data registry.

In 'addition, the 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 comply with verification requirements.

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 rater must report the second failure to the data registry. All the nontested units in the group must be individually field verified and diagnostically tested.

Additional information is in Reference Residential Appendix RA2.6.

### 2.5.6 Installer Requirements and HERS Procedures for Alterations

When compliance for an alteration requires field verification and diagnostic testing by a certified HERS Rater, the building owner may choose for the field verification and diagnostic testing to be completed for each dwelling unit, or as part of a designated sample group of dwelling units for which the same installing company has completed work that requires testing and field verification for compliance. The only alterations that will require HERS testing/verification are HVAC changeouts. The building owner or agent of the building owner must complete the applicable portions of a shorthand version of the certificate of compliance (the CF1R-ALT) form for his or her climate zone. When compliance requires verification, the building owner or agent must arrange for transmittal/submittal of the certificate of compliance information to the data registry, identifying the altered HVAC system and measures that require verification. The building owner must also submit an approved/signed copy of the certificate of compliance to the rater.

When the installation is complete, the person responsible for the performance of the installation must complete the certificate(s) of installation (CF2R). All required certificate(s) of installation must be registered with an approved data registry when field verification and diagnostic testing are required.

After verifying that the certificate of compliance (CF1R-ALT) and all required certificate(s) of installation are completed, signed and registered, the rater must verify compliance. If group sampling is used for compliance, the sampling procedures described in Reference Residential Appendix RA2.6.3.3 and RA2.8, for sampling of 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 cannot approve the alteration until the agency has verified completed, signed and registered certificate of compliance (CF1R-ALT), certificate(s) of installation and certificate(s) of verification documentation for the altered HVAC system. The agency shall also verify that the installing contractor provides copies of all of 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 (HVAC systems) or fewer. When a TPQCP is used, the enforcement agency may approve compliance based on the certificate(s) of installation (CF2R), where data checking has indicated that the unit complies, on the condition that if the required HERS verification procedures determine that resampling, full testing, or corrective action is necessary, such work shall be completed.

### 2.5.7 For More Information

More details on field verification and/or diagnostic testing and the HERS provider data registry are in the 2019 Reference Residential Appendices and 2019 Reference Joint Appendices, as described below:

1. Reference Joint Appendix JA7

2. Reference Residential Appendix RA2

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 measures for compliance. Dwellings that do not have the same HERS measures specified for compliance are not allowed to be placed in the same HERS sample group. If the whole-building compliance approach has been used, all dwellings in the building, have the same HERS features specified. However, if unit-by-unit compliance approach has been used, and all dwellings do not use the same HERS features for compliance, then only the dwellings that have used the same HERS features may be grouped together.

For this example, since duct testing is the only HERS measure 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 first dwelling unit for each model floor plan in the building must be verified by the rater before the start of formation of sample groups.

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. After the 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.

Defining duct location as inside or outside for leakage purposes is not described by the locations of walls or the number of stories. The boundary between inside and outside for leakage purposes is defined by the air boundary, typically drywall, between inside and outside. Spaces between floors and spaces in walls (including interior walls) are often "outside" from an air leakage perspective because they are not sealed effectively to form an air barrier and communicate to the outside.

Duct insulation is not required for ducts in directly conditioned space because there is an expectation that there will be reduced conduction losses for these ducts. To get full credit for ducts in conditioned space, duct leakage must be tested and meet the requirements for duct sealing. In a multifamily building for compliance credit to be taken for ducts in conditioned space, all the duct systems in the building must be in conditioned space unless compliance is documented for each dwelling unit separately. To meet the mandatory requirements, all HVAC units must have ducts made of UL 181 approved materials (that is, cased coils). Coils enclosed by sheetrock do not meet the mandatory requirements.