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A model for energy savings—4 Mort Street Canberra

Key facts: 

  • Improvement from 2 to 4.5 star NABERS Energy rating
  • Investment of $1.5 million with a payback period of as little as one year
  • Increase in asset value estimated at $1.4 million

The ACT Public Trustee House, 4 Mort Street Canberra, had problems common to many ageing commercial buildings. It had a poor energy rating, a heating, ventilation and cooling (HVAC) system near the end of its operational life and some tenancy leases were due to expire.

The building owner’s limited budget of $1 million for capital expenditure was bolstered by a $0.5 million grant from the Australian Government Green Building Fund.

The retrofitting of 4 Mort Street is a great example of how low-cost and undisruptive energy efficiency gains were built in to a 45-year old commercial office building, increasing its NABERS Energy Rating from 2 star to 4.5 star.

Under the Commercial Building Disclosure Program, building owners and lessors are required to disclose the energy efficiency of their buildings, including a NABERS rating, when they are selling or leasing 1000 square metres or more of office space. Mandatory disclosure of clear and credible information about a building’s energy efficiency provides incentive in the marketplace to undertake commercial retrofits.

This is a picture of the building at 4 Mort Street, Canberra, viewed from the street

Figure 1: Street view of 4 Mort Street, Canberra

Retrofit Pathway

The retrofit involved the following key steps:

  1. a Level 2 Energy Audit
  2. a building simulation
  3. upgrades of HVAC plant and lighting systems in common areas
  4. commissioning, monitoring and fine tuning of HVAC system.

Electricity consumption was significantly reduced resulting in annual energy cost savings of $120,000 and a 70 per cent reduction in annual greenhouse gas emissions.

Plant reliability has increased together with improved occupant comfort due to enhanced zoning arrangements and better control.

Asset value is estimated to have increased by $1.4 million with a payback period of as little as one year. This is an aspect of efficiency retrofits that is often overlooked. The largest financial gains are those associated with the increase in asset value and tenancy retail returns following upgrades.

The mandatory disclosure requirements of the Commercial Building Disclosure Program mean building owners can generate rental income that reflects their building’s energy efficiency. It’s another example of how energy efficiency measures make business and environmental sense.