Why Up to 70% of Australian Commercial Buildings Risk a Drop in NABERS Energy Rating?

Here is something that might catch your attention — according to industry projections, up to 70% of Australian commercial buildings could see their NABERS ratingsdrop under the updated methodology. That is not a minor glitch. That is a sector-wide shift. If you own, manage, or lease an office building in Australia, this directly affects your asset value, tenancy negotiations, and regulatory standing.

The NABERS energy rating system has been a benchmark for commercial property performance for years. Yet the rules of the game are changing. This is not just about efficiency upgrades or LED lighting swaps. The updated NABERS methodology now places sharper weight on NABERS electrification and fuel type – meaning buildings that still rely heavily on NABERS gas consumption may find their scores falling fast, even without any change to their actual energy use.

This way, what once seemed like a comfortable 5-star or 6-star rating could shrink to something far less competitive. Therefore, the earlier you understand what is driving this shift, the better positioned you will be to protect your office building rating – and your portfolio.

What Is the NABERS Rating System and Why Does It Matter?

The NABERS rating – short for National Australian Built Environment Rating System – measures the actual operational performance of a building. It covers energy, water, waste, and the indoor environment. For commercial properties, the NABERS energy score is the one that landlords, tenants, and investors pay closest attention to.

A 6-star rating signals market leadership. A 4-star rating meets solid expectations. Anything below that raises eyebrows in lease negotiations. The NABERS impact on commercial properties goes well beyond the number on paper – it shapes rental premiums, green lease obligations, and even access to sustainability-linked finance.

Likewise, with growing pressure from ESG reporting requirements and government disclosure mandates, having a credible NABERS energy score is no longer optional for serious players in the Australian commercial market.

NABERS Star Rating Reference — Commercial Office Buildings

Star Rating	Performance Level	Market Perception
6 Stars	Market-leading	Top-tier asset — highly competitive
5 Stars	Excellent	Above average — attracts premium tenants
4 Stars	Good	Meets green lease and standard requirements
3 Stars	Average	Acceptable but increasingly scrutinised
2 Stars or below	Below average	Potential risk in leasing and finance

The NABERS Methodology Update — What Changed?

The recent NABERS methodology update is not a minor tweak. It introduces a new approach to how fuel types are weighed when calculating a building’s NABERS energy score. Specifically, it applies higher greenhouse gas coefficients to NABERS gas consumption. That means gas-powered systems – heating, hot water, even some cooling equipment – now contribute more negatively to a rating than they once did.

At the core of this shift is a push toward NABERS electrification. The Australian grid is getting cleaner. Therefore, buildings that run on electricity – particularly those with renewable energy inputs – now look comparatively better. Buildings anchored to gas infrastructure look comparatively worse. This way, the update does not penalise energy use volume alone – it penalises the wrong kind of fuel source.

Not only that, but the timing matters. The update coincides with Australia’s broader net-zero commitments and state-level electrification targets. Hereby, buildings that delay action on gas dependency are not just facing a rating drop – they are moving in the opposite direction to where the market is heading.

Key Changes in the NABERS Methodology Update

Factor	Previous Approach	Updated Approach
Gas consumption weighting	Lower greenhouse coefficient	Higher coefficient applied — scores drop for gas-heavy buildings
Electrification credit	Not prominently factored	Buildings with grid or renewable electricity score better
Emissions factor (grid electricity)	Based on older grid mix	Reflects cleaner grid — electricity now more favourable
Impact on NABERS rating fall	Minimal for gas users	Significant — potential drop of 0.5 to 1.5 stars for gas-reliant assets

Which Buildings Are Most at Risk of a NABERS Rating Fall?

Not every building faces the same level of exposure. Buildings most at risk of a NABERS rating fall tend to share a few common traits. Hereby, identifying these early can help owners act before the next rating cycle.

• High NABERS gas consumption — buildings with gas-fired HVAC, boilers, or central heating systems face the steepest drops
• Older office stock — pre-2000 buildings with legacy infrastructure and no fuel switching upgrades
• Mixed-use commercial assets with gas-reliant base building services
• Buildings not yet on a renewable energy tariff or behind-the-meter solar arrangement
• Assets with recent ratings of 3.5 to 4.5 stars — these sit closest to the boundary where a drop becomes visible and damaging

That way, if your building falls into one or more of these categories, the window to act is closing. The next assessment cycle will apply the updated coefficients regardless of when you first rated.

How Does NABERS Gas Consumption Factor Into the Score?

Under the updated framework, NABERS gas consumption is assessed using a revised greenhouse gas emissions factor. Previously, gas was treated relatively favourably because of its lower carbon intensity compared to older coal-heavy electricity grids. That logic no longer applies at the same scale.

As Australia’s electricity grid continues to decarbonise, the emissions factor for grid electricity has dropped. Likewise, NABERS gas consumption now carries a comparatively heavier emissions burden. The result — buildings with the same physical energy use as five years ago are now scoring lower, purely because of the fuel type shift.

This way, a building that uses 500 MJ per square metre annually in gas may now score 0.5 to 1.5 stars lower than it would have under the previous framework – without consuming a single extra megajoule. That is the real sting of the NABERS methodology update.

What Does NABERS Electrification Mean for Commercial Buildings?

NABERS electrification refers to the process of replacing gas-fired or fossil-fuel-based systems with electric alternatives. In a commercial building context, this typically involves switching gas HVAC systems to reverse-cycle electric or heat pump technology, replacing gas hot water systems, and exploring induction alternatives for food service tenants.

Not only that, but NABERS electrification paired with a green power or renewable energy arrangement creates a compounding benefit. The building reduces its direct gas dependency, and its electricity consumption draws on lower-emission sources. Therefore, the NABERS energy score reflects both improvements together.

The upfront cost of electrification is real. Likewise, the long-term payoff – in rating points, tenant attraction, and asset resilience – is also very real. Buildings that move early gain a first-mover advantage in a market where office building ratings are becoming a direct lever in lease pricing.

Electrification Pathway — Common Upgrades and NABERS Impact

Upgrade Type	Replaces	Estimated NABERS Benefit
Heat pump HVAC	Gas-fired heating system	0.5 – 1.0 star improvement potential
Electric hot water system	Gas boiler/storage system	0.2 – 0.5 star improvement potential
Renewable energy tariff / PPA	Standard grid electricity	0.3 – 0.8 star improvement potential
Building energy monitoring system	Manual reporting/estimates	Accuracy improvement, avoids score penalties

What Should Building Owners and Managers Do Right Now?

The NABERS impact on commercial properties is not a future concern – it is already arriving. Hereby, acting now rather than waiting for the next rating assessment is the smarter path. There are a few clear steps worth prioritising.

• Audit current fuel mix — understand exactly how much of your energy use is gas versus electricity
• Model the rating impact — run a scenario analysis using the updated greenhouse gas coefficients to estimate your new NABERS energy score
• Identify electrification opportunities — start with the highest-impact systems (HVAC and hot water)
• Review energy procurement — explore whether a green power or renewable energy agreement can improve your NABERS rating before physical upgrades are complete
• Engage a qualified assessor — work with someone who understands both the technical and commercial dimensions of NABERS electrification

This way, even partial steps taken before your next assessment cycle can meaningfully reduce the scale of any NABERS rating fall.

Why Are Office Building Ratings a Commercial Asset Issue, Not Just a Compliance One?

There is a tendency to treat office building ratings as a tick-box exercise. That framing is becoming expensive. In the current leasing market, major tenants – law firms, financial services companies, government agencies – include minimum NABERS energy requirements in their heads of agreement. A rating drop can literally remove a building from contention for those tenancies.

Not only that, but sustainability-linked loans and green bonds are now written with NABERS rating thresholds as covenants. A rating drop can trigger a margin ratchet or covenant breach. Therefore, the NABERS impact on commercial properties runs directly into balance sheet territory for leveraged owners.

Likewise, as mandatory climate disclosure requirements expand in Australia, a declining NABERS energy score will appear in annual reports and investor briefings. That is not a position any asset manager wants to be in.

Final Thoughts

The NABERS methodology update is a structural shift – not a short-term blip. Buildings anchored to NABERS gas consumption are swimming against the current. The path forward runs through NABERS electrification, smarter energy procurement, and a clearer picture of where your office building rating stands under the new framework.

The risk of inaction is not abstract. A NABERS rating fall affects leasing outcomes, financing costs, and investor sentiment – all at once. Hereby, the buildings that come out ahead will be the ones that treat this as a strategic asset decision, not a compliance formality.

If you are unsure where your building sits under the updated framework, reaching out to a qualified team is the right first step. Eco Certificates works with commercial building owners across Australia to assess NABERS energy exposure, model electrification scenarios, and develop a clear path to protecting – or improving – your NABERS rating.