While the United States does not have a national commercial building energy code, the Department of Energy (DOE) recognizes an energy reference standard and requires states to have a code that is just as stringent to receive code implementation funding.

In February 2024, the DOE issued a determination that ANSI/ASHRAE/IES Standard 90.1-2022, Energy Efficiency Standard for Buildings Except Low-Rise Residential Buildings, increases energy efficiency in commercial buildings by nearly 10% over the previously recognized 2019 version. Within two years of publication, all states must have an energy code at least as stringent.

Commercial building energy codes regulate the design energy efficiency of new buildings and renovations. While some jurisdictions write their own codes, the majority adopt a model such as 90.1 or the International Energy Conservation Code (IECC), both of which are updated every three years.

Based on previous adoption, at least half the states are likely to eventually gain compliance. A majority will adopt a comparable version of the IECC, which recognizes 90.1 as an alternative compliance standard.

Standard 90.1-2022 adds an expanded scope addressing building sites, modest requirements for on-site renewable energy, customizable energy credits, a new mechanical system efficiency performance option, requirements to address thermal bridging and expanded criteria for whole-building air-leakage testing.

Regarding lighting, the 2022 standard adjusted prescriptive power allowances, modified the requirements for alterations, incorporated germicidal and horticultural lighting, and updated several mandatory lighting control requirements. Let’s take a closer look, noting this information is provided for general educational purposes.

Building sites: The scope of Standard 90.1-2022 is clarified to include that the site covers exterior and parking lot lighting that is on-site but not provided through the building’s main electrical panel.

Alterations: If a lighting alteration—including lamp and driver/ballast retrofits—is of a certain size, the 2022 version requires compliance with power allowances and lighting control provisions. If smaller, the alteration must satisfy the power allowances or produce a new wattage at least 50% below the altered system’s original wattage. It must comply with manual local and automatic shutoff control requirements if an interior system, or an off control if it is exterior.

Lighting power allowances: Interior and exterior lighting power allowances were generally reduced. If using the Space-by-Space Method of compliance, the additional interior power allowances for decorative and retail sales lighting were also lowered, while lighting for videoconferencing was added to the standard and granted 0.5W/sq.ft.

Germicidal function: Power used only for a germicidal function was added to the exemption list from being subject to interior lighting power allowances.

Horticultural lighting: Certain horticultural luminaires are required to achieve a minimum efficacy using a photosynthetic photo-efficacy metric. The luminaires must be controlled through an automatic shutoff at specific programmed times.

Occupancy sensing in open offices: Occupancy sensing is required in offices 300 square feet and larger, with control zones limited to 600 square feet. Lighting in these zones can turn on to full power, while neighboring zones, if unoccupied, may turn on to a maximum of 20%. Controlled lighting must turn off within 20 minutes of detected vacancy.

Daylight-responsive controls: Standard 90.1-2022 reduced the wattage threshold for requiring daylight-response control in toplit and primary and secondary sidelit daylight areas.

Exterior lighting controls: A requirement was added that all exterior lighting be furnished with an off control. All exterior lighting must be capable of being reduced by at least 50% of full power in response to scheduling and occupancy sensing.

Guest room controls: Occupancy-based automatic shutoff of lighting and all switched power receptacles is required in guest rooms and suites in hotels, motels and similar buildings. The exemption for captive card key control was eliminated.

Dwelling unit controls: For dwelling units such as living spaces in high-rise multifamily buildings, minimum light source efficacy has been increased to 75 lumens/W and luminaire efficacy to 50 lumens/W. At least 50% of permanently installed luminaires must be controlled by dimmers or automatically turn off within 20 minutes of vacancy. Additionally, permanently installed exterior luminaires dedicated to a dwelling unit may need to be provided with manual control while automatically shutting off based on schedule, occupancy (within 15 minutes) or daylight.

The overall trend in energy codes and standards has been toward reduced power allowances and more detailed control strategies to save energy, and 90.1-2022 improved the model code’s energy efficiency with even stricter requirements.

With 90.1 being the national energy reference standard, ECs may benefit by being familiar with the 2022 version’s requirements.

stock.adobe.com / eneng