Lighting is one of the major contributors to the internal heat gains and energy use of the building. Most energy codes set the maximum amount on lighting energy consumption in terms of Lighting Power Density (LPD). The platform automatically loads the defined maximum LPD when you select the energy code from the Project page. This is based on an area-weighted average of your building type and code version applied to a PNNL Prototype Building.

The platform automated LPD values are referred from ASHRAE Standard 90.1 Table 9.5.1 or the IECC Table C405.3.2(2) for your code version. If a specific local code is selected (e.g. Title 24 for the State of California), then that code manual is referenced to automate the LPD input.

Lighting (W/ft2) | (w/m2): This is an automated input by the platform based on the maximum LPD value. This value varies based on the building type and the energy code version. This value can be modified if additional information about the project is known.

Additionally, the hourly profile can easily be adjusted by a dedicated lighting schedule.

Here are some rule-of-thumb numbers for particular building use types. If you have multiple uses in the space use an area-weighted average to get the overall LPD.

Try to use LED lights to go lower than the below numbers and be sure to ask the lighting designer to lower their lighting as far as possible. These are very conservative assumptions.

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