9.3 Compliance Approaches

Apart from meeting all applicable mandatory requirements as outlined in Section 9.4, an addition or alteration must also demonstrate energy compliance using a prescriptive or performance method.

There are several compliance alternatives or compliance paths to demonstrate that an addition or alteration meets the Energy Standards. Compliance alternatives depend on whether the scope of permitted work is:

1. Addition only where no changes are being made to the existing building except removal of roofs, exterior walls, and floors required as a result of the addition; and removal of any fenestration in those same removed roofs and exterior walls to make way for the addition.

2. Alterations only where there is no addition (that is, no increase in conditioned floor area and volume).

3. Addition and alterations where there are both additions and alterations to the existing building.

For each of these permit scenarios, Table 9-1 summarizes the available compliance approaches for low-rise residential additions and alterations.

Table 9-1: Compliance Alternatives for Residential Additions and Alterations

Project Scope	Prescriptive Approach	Performance Approach^{1, 2}
1. Addition Only:	Additions ≤400 ft²; or	Addition Alone
	Additions >400 ft² and ≤700 ft²
	Additions >700 ft²; or
2. Alteration Only:	Meet All Applicable Requirements for Prescriptive Alterations	Existing + Alterations Without Third Party Verification of Existing Conditions; or
		Existing + Alterations With Third Party Verification of Existing Conditions; or
		Existing + Alterations as All New Construction
3. Addition and Alteration Combined:	Meet All Applicable Requirements for Prescriptive Alterations and a Prescriptive Addition Approach (see Additions Only above)	Existing + Addition + Alterations Without Third Party Verification of Existing Conditions; or
		Existing + Addition + Alterations With Third Party Verification of Existing Conditions; or
		Existing + Addition + Alterations as All New Construction
1) In the performance method, the building must be modeled with Energy Commission-approved compliance software as explained in Chapter 8 of this 'Manual. 2) The Existing + Alterations performance approach with or without third party verification may be used only if there are at least two types of altered components in the existing building. This requirement does not apply to the Existing + Addition + Alterations compliance method.

9.3.1 Additions Only

The prescriptive requirements for new addition construction are listed in §150.2(a)1. Unless otherwise noted, the prescriptive requirements contained in §150.1(c) also apply.

1. Total glazing area up to 75 ft² or 30 percent of the conditioned floor area, whichever is greater.

2. Total glazing area maximum for west facing glazing is 60 ft² or 5 percent in Climate Zones 2, 4, and 6-16.

4. Extensions of existing wood-framed walls may retain the dimensions of the existing walls and require the following cavity insulation:

1. Total glazing area up to 120 ft² or 25 percent of the conditioned floor area.

2. Total glazing area maximum for west-facing glazing is 60 ft² or 5 percent in Climate zones 2, 4, and 6-16.

4. Extensions of existing wood-framed walls may retain the dimensions of the existing walls and require the following cavity insulation:

1. Total glazing area up to 175 ft² or 20 percent of the conditioned floor area, whichever is greater.

2. Total glazing area maximum for west-facing glazing is 70 ft² or 5 percent in Climate zones 2, 4, and 6-16.

3. Extensions of existing wood-framed walls may retain the dimensions of the existing walls and require the following cavity insulation:

Note: Except as noted, all applicable prescriptive requirements for additions must be met when using the prescriptive approach. Otherwise, the building must comply using the performance approach.

For prescriptive additions, a certificate of compliance (CF1R-ADD) form must be completed and submitted for permit. If any mandatory or prescriptive measures require HERS verification and/or testing, the certificate of compliance for the project must be registered online with a HERS Provider before submittal to the enforcement agency. Refer to Section 2.2 and Section 2.5.

Additions may comply using the performance approach by meeting the requirements in §150.2(a)2 and explained further in Section 9.7. The performance options are:

In this compliance scenario, the addition alone is modeled using the compliance software, and the existing building is not modeled at all. This approach may work well when the existing building is not undergoing alterations, and the permitted work scope covers only the addition.

1. Advantages: Data for the existing building are not needed except for the total existing conditioned floor area that is used to calculate the fractional “number of dwelling units” for the addition. The existing building is not modeled and not analyzed for altered components or systems. This typically saves a large amount of time performing the analysis.

2. Disadvantages: The prescriptive allowances for additions do not apply to the addition alone performance approach. If the addition includes a large area of glazing or is otherwise deficient in comparison with the prescriptive requirements, it may be difficult to demonstrate compliance under this approach. Alterations to the existing conditions that improve the energy performance of the existing building cannot be used in this approach as “trade-offs” with the addition.

In this compliance scenario, the entire building is included in the analysis. This approach does not require unaltered existing components to be brought in to compliance.

1. Advantages: This approach offers the most flexibility by modeling improvements to the existing building. The energy budgets include the more generous glazing allowances given to prescriptive compliance.

2. Disadvantages: Plans and data for the existing building are needed, increasing the time and complexity of the calculations.

Demonstrating compliance as a whole new building, which entails combining existing plus the addition as all new construction, is another approach. This approach is used when the addition alone does not comply or changes are extensive. Compliance can be hard to achieve because all existing features must be brought up to the current code.

9.3.2 Alterations Only

Alterations may comply prescriptively by meeting all applicable requirements in §150.2(b), which are explained further in Section 9.6 and summarized in Tables 9-5 and 9-9. Several prescriptive alteration requirements are specific to the building site climate zone. There are also several exceptions to the prescriptive requirements based on either climate zone or other conditions listed in the Energy Standards.

Note: Every applicable prescriptive alteration requirement must be met to use the prescriptive approach; otherwise, the building must comply using a performance approach.

Under the prescriptive alteration approach, the appropriate certificate of compliance (for example, CF1R-ALT or CF1R-ALT-HVAC) form must be completed and submitted for a permit. If any mandatory or prescriptive measures require HERS verification or testing (see Section 2.5, HERS Field Verification and Diagnostic Testing of this manual), the certificate of compliance for the project must be registered online with a HERS Provider (see Section 2.3 of this manual) before submittal to the enforcement agency.

Alterations may comply using the performance approach by meeting the requirements in

1. Existing + Alterations: When two or more types of components or systems are being altered in the existing building, then the existing + alterations performance approach may be used.

2. Compliance Without Third-Party Verification allows for compliance of the alterations without the need for third-party inspection to verify existing conditions being altered.

3. Compliance With Third-Party Verification allows for compliance of the alterations only with third-party inspection to verify existing conditions being altered.

4. Existing + Alterations as new construction: Demonstrating alterations compliance as a whole new building is usually difficult to achieve but still an option. Typically this approach is used when prescriptive alterations cannot meet the prescriptive requirements in Table 150.1-A in the Energy Standards.

Note: Every applicable prescriptive alteration requirement must be met to use the prescriptive approach; otherwise, the building must comply using a performance approach.

9.3.3 Additions and Alterations Combined

When a low-rise residential project includes both an addition and any alterations, the prescriptive requirements for each condition must be met. The addition may comply with any of the prescriptive addition options explained above and documented with the appropriate compliance forms (for example, CF1R-ADD). The alterations must also meet all prescriptive requirements and be documented with the specific compliance forms for alterations (for example, CF1R-ALT, CF1R-ALT-HVAC).

The performance path that includes both additions and alterations is the “Existing + Addition + Alterations” approach. (See Section 9.7.) There are two ways to analyze the building using this method: compliance with third-party verification of all existing conditions altered or compliance without third-party verification.