Powering-up for NABERS Assessment

Ian Van Eerden, Brian Fung

Changes to the Commercial Building Disclosure (CBD) program now requires owners of commercial offices of more than 1000 square metres to provide a valid Building Energy Efficiency Certificate (BEEC) to potential buyers or lessors. As a mid to lower-tier owner, you may have overlooked energy initiatives in the past and feel unprepared for the process of attaining a BEEC. However, a robust NABERS rating and TLA assessment can help to reduce operational costs, strengthen your building’s marketability and increase the capital value of your asset. 

NABERS star rating

The NABERS system looks at the energy usage of your building and normalises it to create a power consumption metric for elements falling under a building manager’s control, like base building HVAC, lighting, lifts and support services. An accredited assessor will award a NABERS star rating in line with a stringent set of rules backed by relevant documentation:

  • Energy bills for the past 12 months (electricity, gas and diesel)
  • Information on all non-utility energy sub-meters
  • Net Lettable Areas (NLA) drawings to the PCA method of measurement
  • Lease contracts indicating the hours a tenancy must be safe, lit and comfortable
  • Schedule of vacancies over the past 12 months
  • Information on after hours air-conditioning requests
  • Drawings that show how the building’s systems are laid out

A NABERS rating is relatively simple to improve, and facilities managers will have the greatest understanding of where productivities may be possible. Data collected suggests that an engaged manager can make a whole star difference to a building’s rating – they know how the building performs and where it can be improved. Often simple things like rationalising plant hours or turning off boilers throughout summer can yield significant improvements in a star rating. 

Tenant Lighting Assessment (TLA)

A TLA assesses the lighting power density for a specific office area.  An assessor will need to walk through the entire building to calculate the total energy used by the lights in each functional space. It can be a time-consuming exercise but fortunately, changes to the scheme will extend the validity of new TLA’s to five years. 

Power density ratings range from ‘very poor’ (typically due to large numbers of halogen or T8 lamps), through to ‘excellent’ (achieved by from LEDs or widespread T5 lamps). The TLA assessment also includes lighting control systems. ‘Poor’ controls usually reflect a single light switch, while an ‘excellent’ rating results from motion sensor controls with lighting zones less than 100m2

Having NLA drawings and actual ceiling plans will speed up the assessment process considerably. Plus, you’ll need to identify the installed lamp power rating and control gear.  It’s important to note that TLA assessors are now permitted to assess a proposed lighting upgrade in addition to the existing system.   

Overall, facilities managers are ideally positioned to streamline the compulsory assessment process for commercial buildings and can help to achieve healthy outcomes for both the building and its owner.  

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