8.2       Compliance Basics

8.2.1          Compliance Process

Any approved computer program may be used to comply with the Energy Standards using the performance method. The following steps are a general outline of the typical computer program procedure:

1.    Collect all necessary data on each component.

a.    For the building envelope, the area of each fenestration, wall, door, roof, ceiling and floor is needed. For each component, the applicable energy characteristics needs to be defined including U-factor, solar heat gain coefficients (SHGC), solar reflectance, and thermal mass values.

b.    For HVAC systems, the type and efficiency of space conditioning equipment are required. For hydronic space heating, the specific water heater type and efficiency are required. For fan-forced conditioning systems, the location and amount of insulation of the duct system are needed.

For domestic hot water systems, the water heater type, quantity, efficiency, and area served will be required, along with the water heating distribution system. Additional information will be required for "built-up" systems.

Other efficiency measures and options can be used to improve building efficiency.

2.    Start by entering the building envelope basic data such as square footage, number of stories, occupancy type, and climate zone. Define each opaque surface with the related orientation, area, and thermal performance properties. Add the fenestration that is associated with each opaque surface, including any fixed shading such as overhangs and side-fins. Enter the data of the equipment and distribution systems for the space conditioning and water heating systems. The input values and assumptions must correctly correspond to the information on the final approved plan set and inputs must be equal to or more energy-efficient than required mandatory measures.

3.    Launch a computer simulation to calculate automatically the TDV energy of the standard design and the proposed design.

For existing buildings where the values of installed features are unknown, default values may be used based on the year of the construction.  Refer to the Default Assumption for Year Built, Table 8-1 at the end of this chapter.

The building energy efficiency complies if all the mandatory measures are met and the total TDV energy use of the proposed design is the same as or less than the standard design TDV energy budget.

When creating a computer input file, use the space provided for the project title information to concisely and uniquely describe the building being modeled. User-designated names should be clear and internally consistent with other orientations and/or buildings being analyzed. Title names and explanatory comments should assist individuals involved in both the compliance and enforcement processes.

8.2.2          Defining the Standard Design

Each approved compliance software program must automatically calculate the TDV energy use of the standard design. The standard design is created based upon data entered for the proposed design using all the correctly fixed and restricted inputs.

The computer program defines the standard design by modifying the geometry of the proposed design and inserting the building features of Table 150.1-A of the Energy Standards. This process is built into each approved computer program, and the user cannot access it. Key details on how the standard design is created and calculated by the computer programs, including the listing of fixed and restricted input assumptions, are documented in the 2016 Residential ACM 'Reference Manual.

The standard design assumes the same total conditioned floor area and volume as the proposed design and the same gross exterior wall area as the proposed design except that the wall area in each of the four cardinal orientations is divided equally. The standard design uses the same roof/ceiling area, raised floor area, slab-on-grade area, and perimeter as the proposed design but uses the standard insulation R-values required in Table 150.1-A of the Energy Standards.

Total fenestration area in the standard design is equal to the proposed design if the fenestration area in the proposed design is less than or equal to 20 percent of the floor area; otherwise, the fenestration area of the standard design is equal to 20 percent of the floor area. Fenestration area in the standard design is evenly distributed among the four cardinal orientations. SHGC and U-factors are the same as those listed in Package A, and no fixed shading devices such as overhangs are assumed for the standard design.

The standard design includes minimum efficiency heating and cooling equipment, as well as the minimum duct R-value and the location of the ducts, depending on whether Option A, B, or C is used from Table 150.1-A of the Energy Standards. Ducts are assumed to be sealed as required by §150.0(m). The standard design also assumes correct refrigerant charge as required by §150.1(c)7A.

For water-heating systems that serve dwelling units, the standard design is a 50 gallon gas storage water heater with an energy factor equal to the federal minimum standard. The standard design has a trunk-and-branch distribution system that includes the assumption that all mandatory measures are met (that is, the first 5 feet of hot and cold water piping from heating source) and that all piping ¾- inch or larger is insulated and the entire length of piping to kitchen fixtures are insulated as specified in §150.0(j)2A or §150.0(j)2B.

For multiple dwelling-unit buildings, either a central distribution system may be used or a water heater may be installed in each unit. The standard design system type is based on what the proposed design uses. However, the standard design does include a pumped recirculation system that is controlled by hot water demand and hot water return temperature.

8.2.2.1      Standard Reports

For consistency and ease of enforcement, the manner in which building features are reported by compliance software programs is standardized. Energy Commission-approved compliance software programs must automatically produce compliance reports in this standard format. The principal report is the certificate of compliance (CF1R-PRF-01-E).

The CF1R-PRF-01-E has two highly visible sections, one for special features and modeling assumptions, and a second for features requiring field verification and/or diagnostic testing by approved HERS Raters. These two sections serve as a punch list for special consideration during compliance verification by the local enforcement agency and the HERS Rater. Items listed in the Special Features and Modeling Assumptions section indicate that unusual features or assumptions are used for compliance, and they call for special care by the local enforcement agency. Items listed in the HERS Required Verification section are for features that rely on diagnostic testing and independent verification by approved HERS Providers/Raters to ensure proper field installation. Diagnostic testing and verification by HERS Providers/Raters is in 'addition to local enforcement agency inspections.

8.2.3          Professional Judgment

Some modeling techniques and compliance assumptions applied to the proposed design are fixed or restricted. There is little or no flexibility to choose input values for energy compliance modeling. However, other aspects of energy modeling remain for which some professional judgment may be acceptable or necessary. In those instances, the compliance software user must exercise proper judgment in evaluating whether a given input is appropriate.

Enforcement agencies have discretion to reject a particular input if the permit applicant cannot substantiate the value with supporting documentation or cannot demonstrate that appropriate professional judgment has been applied.

Two questions may be asked to resolve whether professional judgment has been applied correctly in any particular case:

1.    Is a simplified input or assumption appropriate for a specific case? If simplification reduces the predicted energy use of the proposed building or reduces the compliance margin when compared to a more explicit and detailed modeling assumption, the simplification is not acceptable. That is, simplification must reflect the same or higher energy use than a more detailed model and reflect the same or lower compliance margin when comparing the standard and proposed TDV energy.

2.    Is the approach or assumption used in modeling the proposed design consistent with the approach or assumption used by the compliance software when generating the standard design energy budget?

One must always model the proposed design using the same assumption and/or technique used by the compliance software manager when calculating the energy budget unless drawings and specifications indicate specific differences that warrant energy compliance credits or penalties.

Any unusual modeling approach, assumption, or input value should be documented with published data and should conform to standard engineering practice.

For assistance in evaluating the appropriateness of particular input assumptions, call the Energy Hotline or call the vendor of the compliance software program.