NABERS, Green Star and lighting performance

NABERS Energy is a measured argument. Green Star is a credited argument. Lighting sits in both, and in neither is it a lifestyle photograph. I edit energy claims for a living in Brisbane, and I still see fit-out reports that treat a Section J illumination power density as if it were a NABERS star. It is not. One is a construction-code budget. The other is a year of invoices and meters.

This essay is the lighting slice of those two systems. It lives in standards and compliance because ratings are rules, and in energy and controls because the only lighting strategy a meter respects is hours times watts.

NABERS Energy in one honest paragraph

NABERS rates the measured energy use of a building, a tenancy or a base building against a peer benchmark, then expresses the result in stars. The rules manuals, the rating period and the inclusions matter. So do the hours the building actually ran. Lighting is one end-use among several. In an office it is visible. In a hospital or a data-adjacent commercial floor it can be drowned by other loads. Either way, the assessor does not award stars for a pretty luminaire schedule.

If you want lighting to move a NABERS needle, you must change the electricity that the rating sees. That means fewer watts, fewer hours, or both, on circuits that sit inside the rating boundary. A tenant who replaces T5 panels on a landlord’s unmetered riser may improve their own comfort and do nothing for the base-building rating. Draw the boundary first. Then audit what is inside it.

Metering is the lighting design the assessor can touch

I will argue for lighting meters even when the rating tool does not strictly demand them. A submeter on house lighting, another on the car park, another on façade and signage, and clear tenant check-meters turn arguments into numbers. Without them, every saving is a story and every summer is HVAC’s fault.

Good metering practice for lighting:

• Align meters with the rating boundary and with the BMS graphics.
• Capture interval data, not only a monthly pulse that facilities ignore.
• Include after-hours and cleaner circuits. Those are where Australian offices bleed.
• Do not hide emergency maintained fittings in a way that makes a dark-test look like an energy win.
• Keep a one-page map so the next assessor is not reverse-engineering the switchboard.

If the project has DALI, do not confuse driver-level energy reporting with a NABERS meter. Useful, yes. A substitute for a revenue-adjacent meter on the rating boundary, no.

Lighting power, hours and the measures that actually rate

The measures that show up in a later rating are boring:

• Replace inefficient sources with specified LED, not a random tube, using the retrofit method.
• Cut after-hours lighting with scenes, absence detection and an off that stays off.
• Daylight-dim the perimeter if the blinds and the zone match the glass. See daylight.
• Stop lighting empty meeting rooms at 100 per cent because the sensor was set by a fearful contractor.
• Clean and maintain so the owner does not add fittings to chase a dirty grid. See maintenance.

The measures that look good in a Green Star workshop and then vanish on the meter: tunable-white “circadian” overheads left on a bright scene all day; RGB feature tape on a 24-hour circuit; a daylight credit with no commissioning. I do not mind feature lighting. I mind unmetered feature lighting on the house board.

Use the TCO method to choose among legal options. Do not use a NABERS marketing slide to skip AS/NZS 1680. A gloomy floor can save energy and still be a defective workplace.

Base building, tenancy and the political load

Australian commercial offices split responsibility. The landlord lights the lobby, the toilets, the car park, the façade and sometimes a base-building grid in the tenancy. The tenant adds supplementary lighting, decorative pendants and a server room that was not in anyone’s model. NABERS has products for these splits. Green Star has scopes for these splits. Your lighting specification must name who owns each fitting family or the rating will inherit a fight.

I ask for a responsibility schedule before schematic design ends:

• Base-building lighting circuits and meters.
• Tenant supplementary lighting and how it is metered.
• After-hours operation and who pays.
• Exterior and signage, including any council curfew.
• Car park and loading — often the quiet NABERS leak.

A tenant “lighting upgrade” that leaves the landlord’s 24-hour car park untouched can still be worth doing. Just do not print it as a building rating strategy.

Green Star is evidence, not a vibe

Green Star, under the Green Building Council of Australia, awards credits against a tool version for design and as-built performance. Lighting typically appears in indoor environment, energy, and sometimes in commissioning and metering credits. Visual comfort, glare, colour quality and occupant control are not the same credit as lighting power density. Read the tool. Name the version.

What I put in a Green Star lighting file:

• The illuminance and glare method from 1680 and from the glare essay.
• Lighting power against the NCC and any tighter project target.
• Control narrative and commissioning records, including photocell calibration.
• Metering schematic and sample data.
• Colour documentation if the credit asks for CRI or a TM-30 story.
• Accessibility notes where inclusive design was claimed. See accessible lighting.

Assessors have learned to ask for as-built photographs of sensors that the drawings invented. Give them the photographs. Give them the specification clause that banned the substitution.

Green Star and NABERS meet in commitment agreements and in owners who want a design rating followed by an operational rating. Design the meters in the first document. Retrofitting meters after occupation is possible and miserable.

Climate, hours and the Queensland problem I keep seeing

A Brisbane floor with northern glass and a culture of early starts does not behave like a Hobart civic office. Climate zone changes sky, HVAC penalty and occupancy. It does not change the need to measure. I have watched tropical buildings claim daylight dimming while occupants ran blinds and desk lamps through a wet-season glare. The NABERS year then looked like “lighting didn’t do much”. Lighting did exactly what the blinds allowed.

Tom’s climate piece is the hardware half. My half is: do not import a Sydney after-hours profile into a 24-hour precinct building and then blame the rating tool.

What I will not put in a rating report

I will not attribute a star jump to lighting without a meter or a defensible end-use split. I will not recycle a Section J number as an operational result. I will not hide a dark emergency path in an energy win — 2293 is still in force when the assessor visits. I will not accept “up to 90 per cent” as a NABERS input.

Ratings are one way Australian buildings tell the truth. Lighting can help them if you specify, meter and commission. It cannot help them if you only render a green dash on a slide.

If you have a metering layout that made a rating easier, or a credit that failed because a sensor was substituted, pitch it through write for us. The editorial standards are why we would rather publish the failed credit.