10.3 High-Efficacy Lighting & Lighting Controls (R404)

10.3 High-Efficacy Lighting & Lighting Controls (R404)

Quick Answer: 2021 R404.1 requires all permanently installed lighting fixtures, excluding kitchen appliance lighting fixtures, to contain only high-efficacy lighting sources — not the 2018 90% rule. High-efficacy light sources are defined as lamps of not less than 65 lumens per watt or luminaires of not less than 45 lumens per watt. Interior fixtures need a dimmer, occupant sensor, or other control in or on the fixture, with exceptions for bathrooms, hallways, exterior fixtures, and safety/security lighting. Exterior lighting totaling more than 30 watts needs manual on/off that still allows automatic shutoff, daylight shutoff, and overrides that restore automatic operation within 24 hours.

Lighting is 2021 IECC residential syllabus that Exam 79 job tasks can test. It is not a fifth outline domain with its own percentage. Independent OpenExamPrep material covers R404 because the prescriptive path is R401 through R404, and Tables R405.2 and R406.2 still list R404.1 and R404.2 on the performance and ERI paths.

R404.1 — all permanent fixtures, not 90 percent

All permanently installed lighting fixtures, excluding kitchen appliance lighting fixtures, shall contain only high-efficacy lighting sources.

Three words do the 2021 work: all, only, and the kitchen-appliance exclusion.

The 2018 IECC used a 90 percent high-efficacy rule for permanently installed lighting. Candidates who last sat a 2018 book, or who memorized a builder's "we put LED in 80 percent of the cans" talking point, will pick the wrong option. 2021 does not score a dwelling that is "mostly LED." If a permanently installed fixture is not a kitchen appliance lighting fixture, it shall contain only high-efficacy sources.

Scenario. A permit note says LED lighting in 80 percent of permanently installed fixtures, with incandescent remaining in the living-room cans, leftover from a 2018 checklist. That note fails R404.1. Eighty percent is not a 2021 threshold. Ninety percent is not a 2021 threshold either. The living-room cans are permanently installed fixtures. They shall contain only high-efficacy sources. There is no 20 percent incandescent allowance in the 2021 residential text.

Kitchen appliance lighting fixtures are the exclusion — the lamp that is part of a listed kitchen appliance (a range-hood lamp that is the appliance's lighting fixture, the lamp in an over-the-range microwave that is integral to that appliance). Permanently installed under-cabinet tape lights, ceiling cans over the island, and pantry fixtures are building lighting, not appliance lighting. They must be high-efficacy.

The 2021 high-efficacy definition

Chapter 2 defines high-efficacy light sources as any lamp with an efficacy of not less than 65 lumens per watt, or luminaires with an efficacy of not less than 45 lumens per watt.

Those two thresholds are not interchangeable. A replacement lamp in a socket is judged as a lamp at ≥ 65 lm/W. A luminaire submitted as a complete fixture is judged at ≥ 45 lm/W. Do not invent a third percentage (such as "80 percent of fixtures" or "90 percent of lamps") and call it high-efficacy. Do not assume every product labeled LED meets 65 or 45 without a listing. Decorative low-efficacy lamps in a permanently installed dining chandelier fail even if the rest of the house is LED.

On plan review, the lighting schedule should identify sources as high-efficacy under that definition. In the field, look at what is actually in the socket at final: a high-efficacy can with a low-efficacy bulb swapped in before occupancy is still an R404.1 failure.

Exterior lighting and C405.5 (R404.1.1)

Connected exterior lighting for residential buildings shall comply with Section C405.5 (IECC commercial exterior lighting power), with these exceptions:

1. Detached one- and two-family dwellings
2. Townhouses
3. Solar-powered lamps not connected to any electrical service
4. Luminaires controlled by a motion sensor
5. Lamps and luminaires that comply with Section R404.1

Exam 79's typical detached house is exception 1. Townhouses are exception 2. Those two exceptions are the usual Exam 79 residential case: the dwelling is excepted from C405.5. Do not open ASHRAE 90.1 Section 9.4.2 as the 2021 first-printing pointer — that citation is a 2024 / overlay trap. The first-printing lookup is C405.5.

A Group R-2 building that is still an IECC residential building (three stories or less) can be in the C405.5 net unless another exception applies. Motion-sensor luminaires and R404.1-compliant lamps or luminaires are also out of that C405.5 pointer. Solar path lights that are not on electrical service are exception 3; they are also not connected exterior lighting in the ordinary sense of R404.1.1.

R404.1 still applies to permanently installed exterior fixtures that are building lighting: they shall contain only high-efficacy sources unless they are kitchen appliance fixtures (they are not). Exception 5 of R404.1.1 is how many exterior residential luminaires leave the C405.5 pointer — they already comply with R404.1.

Fuel gas lighting (R404.1.2)

Fuel gas lighting systems shall not have continuously burning pilot lights. Chapter 2 defines a continuously burning pilot light as a small gas flame used to ignite gas at a larger burner that remains in operation until manually interrupted. Decorative gas lanterns with standing pilots fail this subsection. Intermittent or interrupted ignition is the energy-conserving alternative the prohibition is aiming at. This is a lighting rule, not the R403.10 pool-heater pilot rule, though the idea is similar.

Interior lighting controls (R404.2)

Permanently installed lighting fixtures shall be controlled with either a dimmer, an occupant sensor control, or other control that is installed or built into the fixture.

A plain on/off toggle that is not a dimmer, not an occupant sensor, and not some other control in or on the fixture does not satisfy R404.2 for a space that is not excepted. "Other control installed or built into the fixture" covers integral vacancy or occupancy sensors, integral dimming drivers with a listed control, and similar fixture-mounted devices. A breaker in the panel is not a lighting control under this section.

Dimmer and occupant sensor control are defined terms: a dimmer continuously varies light output and energy use; an occupant sensor detects presence or absence and regulates lighting accordingly. Either device, or another qualifying control in the fixture, satisfies the charging sentence.

Interior control exceptions

Lighting controls shall not be required for the following:

Scenario. A full bath has a ceiling luminaire on a standard snap switch and no dimmer. The builder asks whether to add a dimmer for energy. Under R404.2, bathrooms are excepted. Do not write a correction requiring a dimmer or occupant sensor in that bathroom for R404.2. The fixture still shall contain only high-efficacy sources under R404.1. The hallway outside can also use a plain switch. The bedroom and living room on the same permit cannot hide behind the bathroom exception: those permanently installed fixtures need a dimmer, occupant sensor, or other control installed or built into the fixture.

Safety or security lighting is a designed function, not a sticker that says "security" on a living-room can. Egress lighting and site security lighting that is designed for that purpose fit the exception. A chandelier labeled security on a punch list does not.

Exterior lighting controls (R404.3)

Where the total permanently installed exterior lighting power is greater than 30 watts, the permanently installed exterior lighting shall comply with all of the following:

1. Lighting shall be controlled by a manual on and off switch which permits automatic shut-off actions. Exception: lighting serving multiple dwelling units.
2. Lighting shall be automatically shut off when daylight is present and satisfies the lighting needs.
3. Controls that override automatic shut-off actions shall not be allowed unless the override automatically returns automatic control to its normal operation within 24 hours.

Greater than 30 watts is a power total, not a fixture count. Five 6-watt luminaires equal 30 watts, which is not greater than 30, so R404.3 does not trigger on that arithmetic. Five 7-watt luminaires equal 35 watts, which does. Solar lamps not on electrical service do not add to connected lighting power.

Item 1 still needs a manual on/off, but that switch must permit automatic shut-off — a switch that defeats the photocell forever is not this control. Lighting serving multiple dwelling units is excepted from that manual-switch item (typical common-entry lighting on a small R-2). Items 2 and 3 still describe daylight shutoff and the 24-hour override limit for the installation as a whole when R404.3 applies.

Item 2 is a photocell, astronomical time clock, or equivalent daylight shutoff. Item 3 is the override leash: a bypass that leaves the lights in manual-on until someone remembers next month fails; the override shall restore automatic operation within 24 hours.

R404.3 is part of the prescriptive R401-through-R404 stack. Tables R405.2 and R406.2 list R404.1 and R404.2 but do not add a separate R404.3 row. Do not tell a performance applicant that exterior photocells are imaginary; also do not invent an R404.3 citation as a mandatory performance-table line if the item is testing Table R405.2.

Putting R404 together at final

1. Every permanently installed fixture that is not kitchen appliance lighting contains only high-efficacy sources (≥ 65 lm/W lamps or ≥ 45 lm/W luminaires).
2. Interior fixtures in non-excepted rooms have a dimmer, occupant sensor, or other built-in or installed control.
3. Bathrooms, hallways, exterior fixtures, and safety or security lighting are excepted from R404.2, not from R404.1.
4. Fuel gas lighting has no continuously burning pilot.
5. If connected exterior lighting power is > 30 W, check manual on/off that allows auto shutoff (unless serving multiple dwelling units), daylight shutoff, and 24-hour override restore.
6. Detached one- and two-family dwellings and townhouses are excepted from the R404.1.1 pointer to C405.5; other residential buildings might have to meet C405.5. Do not substitute ASHRAE 90.1 Section 9.4.2 for that first-printing lookup.

Exam traps

• All permanent fixtures (minus kitchen appliance lighting), not 90% and not 80%.
• High-efficacy = 65 lm/W (lamps) / 45 lm/W (luminaires), from the 2021 Chapter 2 definition.
• A bathroom without a dimmer is allowed under R404.2.
• Exterior control threshold is greater than 30 watts; override restore is 24 hours.
• Continuously burning pilots are prohibited on fuel gas lighting.
• First-printing R404.1.1 points to C405.5, not ASHRAE 90.1 Section 9.4.2 (a 2024/overlay trap). Detached houses and townhouses are excepted from C405.5.