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Plug Load Modeling

2016 Title 24 CASE Topics

Measure Overview

In this CASE Report, the Statewide CASE Team proposes updated rulesets used to estimate energy use of MELs and lighting in residential homes. MELs are defined in this report as appliances or electronic devices that are generally plugged in to a receptacle, such as white goods and consumer electronics, while lighting includes all portable and hardwired interior, exterior, and garage lighting. Current rulesets contained in the Residential ACM Reference Manual used to model annual energy use of MELs and lighting in residential buildings are based on equations contained in the California HERS Technical Manual. These equations do not account for the significant advances in energy efficiency that have been achieved over the past several years, changes in technology, introductions of new end uses, and/or updates to state and federal energy efficiency standards. Furthermore, existing rulesets do not individually account for major consumer electronics, such as televisions, set-top boxes, and computers, which are all now considered significant end uses. There have also been concerns that the existing rulesets are not accurate for large residential buildings.

To update the rulesets contained in the Residential ACM, the Statewide CASE Team researched energy efficiency trends and mandatory standards for MEL end uses. In addition to creating separate models for appliances and white goods previously included in the Residential ACM rulesets, the Statewide CASE Team isolated the largest miscellaneous loads, such as TVs, computers, and set-top boxes, and developed individual models for each. Additionally, the Statewide CASE Team created updated rulesets for modeling lighting energy use.

The proposed changes would modify the calculation procedures and assumptions used in estimating energy use from MELs and lighting in newly-constructed residential buildings. These changes would not add a compliance option or a new code requirement, but would affect the way that residential building energy use is modeled.

The complete definition of MELs: A miscellaneous electric load is the energy consumed by an appliance or electronic device that can be plugged in to a receptacle or receptacle outlet or hard-wired (connected permanently to a building electrical system) and that is not related to: hardwired lighting, HVAC that is fixed in place (non-portable), water heating, domestic and service water pumps and related systems that are fixed in place (non-portable), renewable power, process loads, swimming pools, spas, saunas, elevators, escalators, moving walkways, transit systems, or electric vehicle charging. In this CASE Report, portable lighting is considered in the same end use group as hardwired lighting; therefore, portable lighting is excluded from the scope of MELs

Stakeholder Meeting

Several stakeholder meetings and CEC staff workshops were held regarding the Nonresidential HVAC Economizer Modifications building energy efficiency topic. The list of past meetings and hearings can be found here. If you would like to receive email updates on this CASE topic, click the link below.


  1. Final CASE Report