## 8.1 Overview

This chapter explains the performance method of complying with the 2019 Building Energy Efficiency Standards (Energy Standards). The method works by calculating an Energy Design Rating (EDR). The EDR is a score from 0 to 100, where 0 represents a building that has zero net energy consumption based on the time-dependent valuation ((TDV) energy consumption and 100 represents a building that is minimally compliant with the 2006 International Energy Conservation Code. This is the same criteria for a score of 100 for the National Home Energy Rating System (NatHERS). Approved programs calculate an EDR for the building (proposed efficiency) and compare it to the energy budget (standard efficiency). Approved compliance programs also calculate an EDR for proposed photovoltaic (PV)/demand flexibility and compare it to standard PV/flexibility budget.

The standard efficiency includes water heating, space heating, space cooling, indoor air quality (IAQ) fan energy, and solar generation. Energy use from lighting, kitchen appliances, and washers/dryers is not eligible to be traded off.

The Energy Commission approved computer programs for compliance calculate space-conditioning and water-heating energy use in accordance with a set of rules. Modeling capabilities are in the 2019 Residential ACM Reference Manual (ACM Reference Manual). All software programs use the same compliance generation tool (California simulation engine [CSE]) to simulate the energy use, and the same report generator to create the certificate of compliance (CF1R), as the public domain program CBECC-Res. Vendors of approved software have the flexibility to create their own user interface, user documentation, and additional forms.

This method provides maximum flexibility to trade off the energy performance of different building components to achieve compliance. Making a building more efficient will lower utility bills and improve comfort.

The performance method is the most popular compliance method allowing builders the flexibility to optimize performance at the lowest cost. Each approved program is required to have a compliance supplement with information on the use of the software as specified in the 2019 ACM Approval Manual.

A discussion of the performance method with additions and alterations is in Chapter 9.