The national model energy standard referenced by the IECC and adopted in 40+ states. Section 9 governs interior and exterior lighting power density limits, mandatory controls, and compliance paths for commercial buildings.
Applies to commercial buildings and high-rise residential buildings. Excludes single-family residences, multifamily buildings of three stories or less, and buildings using less than 3.4 BTU/h·ft² of fossil fuel energy.
All mandatory provisions must be met. Then choose between the Building Area Method or Space-by-Space Method for demonstrating LPD compliance. Both paths require all mandatory controls.
Compliance documentation must identify the compliance method used, list all spaces and their LPDs, confirm all mandatory controls are installed, and be made available to the AHJ upon request.
ASHRAE 90.1 provides two methods for demonstrating interior lighting power compliance. Both require all mandatory provisions in Section 9.4.
Each space type is assigned its own LPD limit from Table 9.6.1. The installed power for each space must not exceed the limit for that space type. More granular — preferred for mixed-use or complex buildings.
A single LPD limit applies to the entire building based on its primary occupancy type from Table 9.5.1. Simpler to document but less flexible — the whole building must comply as one budget.
Maximum Lighting Power Density (W/ft²) by building type. Total installed power for the building must not exceed: LPD × Gross Floor Area.
| Building Type | LPD — 90.1-2022 (W/ft²) | LPD — 90.1-2019 (W/ft²) | Change | Notes |
|---|---|---|---|---|
| Automotive Facility | 0.75 | 0.82 | ↓ | Service bays, showrooms, offices |
| Convention Center | 0.82 | 0.87 | ↓ | Exhibit halls, meeting rooms |
| Courthouse | 0.89 | 0.93 | ↓ | Courtrooms, offices, lobby |
| Dining — Bar/Lounge/Leisure | 0.99 | 1.07 | ↓ | Ambient + decorative allowance |
| Dining — Cafeteria/Fast Food | 0.80 | 0.90 | ↓ | |
| Dining — Family | 0.89 | 0.89 | — | |
| Dormitory | 0.61 | 0.61 | — | Residential spaces + common areas |
| Exercise Center | 0.72 | 0.72 | — | |
| Fire Station | 0.67 | 0.71 | ↓ | |
| Gymnasium | 0.94 | 1.00 | ↓ | Court + support spaces |
| Health Care Clinic | 0.87 | 0.87 | — | Outpatient only; hospital = higher |
| Hospital | 1.05 | 1.05 | — | Includes all clinical + support areas |
| Hotel/Motel | 0.75 | 0.82 | ↓ | Guest rooms + common areas |
| Library | 0.83 | 0.83 | — | |
| Manufacturing Facility | 0.82 | 1.11 | ↓↓ | Significant reduction in 2022 |
| Motion Picture Theater | 0.76 | 0.76 | — | |
| Multi-family | 0.51 | 0.51 | — | High-rise residential (4+ stories) |
| Museum | 0.96 | 1.02 | ↓ | Exhibit + support areas |
| Office | 0.64 | 0.79 | ↓↓ | Significant reduction in 2022 |
| Parking Garage | 0.15 | 0.18 | ↓ | Interior parking structure |
| Penitentiary | 0.78 | 0.81 | ↓ | |
| Performing Arts Theater | 1.19 | 1.39 | ↓ | Stage lighting excluded per 9.1.4 |
| Police/Fire Station | 0.87 | 0.87 | — | |
| Post Office | 0.71 | 0.74 | ↓ | |
| Religious Building | 0.72 | 0.72 | — | Sanctuary + support areas |
| Retail | 0.84 | 1.05 | ↓↓ | General retail; see Table 9.6.1 for accent |
| School/University | 0.72 | 0.87 | ↓↓ | Classrooms, admin, common areas |
| Sports Arena | 0.91 | 0.91 | — | Practice facility only; competition = higher |
| Town Hall | 0.72 | 0.72 | — | |
| Transportation | 0.70 | 0.70 | — | Airports, train stations, bus terminals |
| Warehouse | 0.45 | 0.58 | ↓ | Storage + distribution |
| Workshop | 1.05 | 1.05 | — |
LPD limits by individual space type. Only selected high-use commercial space types are shown. Refer to the full ASHRAE 90.1-2022 standard for the complete table.
| Space Type | Building Category | LPD — 2022 (W/ft²) | LPD — 2019 (W/ft²) | Controls Required |
|---|---|---|---|---|
| Office — Enclosed (≤250 ft²) | Office | 0.72 | 0.98 | Occ sensor + daylight if applicable |
| Office — Enclosed (>250 ft²) | Office | 0.72 | 0.98 | Occ sensor + daylight if applicable |
| Office — Open Plan | Office | 0.55 | 0.61 | Occ sensor required |
| Conference / Meeting Room | Office | 0.90 | 0.97 | Occ sensor + dimming |
| Corridor / Transition | Common | 0.41 | 0.41 | Occ sensor — reduce to 20% when vacant |
| Lobby — Office/General | Common | 0.71 | 0.84 | Daylight zone controls if applicable |
| Lobby — Hotel | Hotel | 0.95 | 1.06 | Dimming required |
| Stairway | Common | 0.49 | 0.49 | Occ sensor — reduce to 20% |
| Restroom | Common | 0.63 | 0.63 | Occ sensor required |
| Storage / Warehouse — Medium Bay | Industrial | 0.58 | 0.58 | Occ sensor required |
| Storage / Warehouse — Fine Material | Industrial | 0.69 | 0.69 | Occ sensor required |
| Classroom / Lecture / Training | Education | 0.72 | 0.81 | Occ sensor + daylight controls |
| Gym — Exercise Area | Exercise | 0.72 | 0.72 | Occ sensor required |
| Lounge / Breakroom | Office | 0.59 | 0.59 | Occ sensor required |
| Electrical / Mechanical Room | Common | 0.42 | 0.42 | Occ sensor required |
| Kitchen — Commercial | Food Service | 1.00 | 1.21 | Occ sensor or auto-shutoff |
| Dining — Family / Casual | Food Service | 0.65 | 0.65 | Dimming + occ sensor |
| Retail — Sales Area (General) | Retail | 0.84 | 1.10 | Daylight + occ as applicable |
| Retail — Accent (Addl. Allowance) | Retail | +0.40 | +0.40 | Additional allowance for display lighting |
| Patient Room | Healthcare | 0.62 | 0.62 | Occ sensor; night mode required |
| Exam / Treatment Room | Healthcare | 1.15 | 1.66 | Occ sensor; task + ambient separation |
| Parking — Interior | Parking | 0.15 | 0.19 | Occ sensor — reduce to 30% when vacant |
These controls are required in ALL compliance paths. They are not optional and cannot be traded off against LPD credits.
Lighting in all spaces ≤5,000 ft² must have automatic shutoff via occupancy sensor or scheduled time clock. Time clock must have 7-day, holiday, and manual override.
Each space enclosed by ceiling-height partitions shall have at least one control device to independently control the general lighting. Switch or dimmer must be readily accessible.
Lighting in daylight zones must be independently controllable from non-daylit zones. Sidelit zones >120 ft² and toplit zones require photosensor-based dimming or stepped switching.
Required in: enclosed offices ≤250 ft², conference rooms, copy/print rooms, break rooms, restrooms, storage rooms, janitorial closets, and other spaces as required in Table 9.6.1.
All exterior lighting must be controlled by a combination of a photosensor and time switch, or an astronomical time switch. Motion sensors may provide partial-off control.
Display and accent lighting must be controllable independently from general lighting. Hotel guest room controls must include a master shutoff at the room entry that turns off all fixed luminaires.
Maximum exterior lighting power for site and building envelope. Values are in addition to any separately permitted parking structure lighting.
| Exterior Application | Lighting Zone | Maximum Power | Unit |
|---|---|---|---|
| Parking Areas & Drives | LZ2 | 0.10 | W/ft² paved area |
| Parking Areas & Drives | LZ3 | 0.13 | W/ft² paved area |
| Building Facades | LZ2 | 0.10 | W/ft² façade area |
| Building Facades | LZ3/LZ4 | 0.15 | W/ft² façade area |
| Walkways (narrow, <10 ft) | LZ2 | 0.70 | W/linear ft |
| Walkways (wide, ≥10 ft) | LZ2 | 0.14 | W/ft² walkway area |
| Plaza Areas | LZ2 | 0.13 | W/ft² plaza area |
| Main Entry (per door) | LZ2 | 20 | W per door |
| Other Doors / Entries | LZ2 | 10 | W per door |
| Sales Canopy | All | 0.60 | W/ft² canopy area |
| Drive-Through Window | All | 400 | W per lane |
| Outdoor Dining | LZ2 | 0.65 | W/ft² dining area |
| Vehicle Service Area (outdoor) | All | 0.25 | W/ft² service area |
Emergency lighting required by life-safety codes (NEC Article 700) is exempt from Section 9 LPD and control requirements. Never apply occupancy sensors or dimmers to emergency circuits.
Lighting for theatrical, performance, and broadcast studio applications is exempt from LPD limits. Production lighting systems are excluded from the building's LPD budget calculation.
Lighting required for industrial or manufacturing processes, medical procedures, or research that cannot be reduced without affecting the process is exempt from the standard.
Lighting inside display cases with transparent fronts is exempt from LPD limits. Lighting for art objects on loan from a museum or gallery is also exempt.
Spaces where the total installed lighting power is less than 100W are exempt from LPD requirements but must still comply with all mandatory control provisions.
Externally illuminated signs and internally illuminated signs are exempt from exterior LPD limits but must be controlled to turn off or reduce ≥30% after business hours per Section 9.4.3.