Initial findings of our research.

Building data, energy usage and costs

This information is based on level-2 energy audits conducted of 15 high, mid and low-rise Sydney apartment buildings (common areas only).

• The total number of apartments in all 15 buildings is 508. The number of storeys of buildings vary from 2 to 10.
• The total electricity consumed by common areas and central building services is 961MWh pa, this equates to greenhouse emissions of approximately 1 kilotonne of carbon dioxide
• The average per unit electricity consumption of the apartment buildings is 1.9 MWh/unit. The lowest per unit electricity consumption was 0.6MWh/unit, this was for a 2-storey building with 18 units. The highest per unit electricity consumption was 3.6MWh/unit, this was for a 7-storey building with 36 units.
• The total cost of common area electricity usage is $210,000 Ex GST for the year 2011/12. Costs for the year 2012/13 are estimated to be 12% higher.
• The average per unit cost of common area electricity consumption is $411 Ex GST pa.

The per-unit electricity usage of buildings was found to not be a good indicator or energy performance. Sites with very low per-unit electricity usage were found to have significant sources of energhy wastage and were able to reduce energy usage through cost effective upgrades.

Energy savings

In total across all 15 apartment buildings energy savings of 48% could be easily achieved by standard energy saving measures such as upgrading lighting and ventilation systems. The energy savings are cost effective too, with a payback on investment of only 2 years.

The energy savings would save a total of $112k per year and reduce greenhouse emissions by 487 tCO2, equivalent to taking 160 cars off the road.

Typically we say energy audits may identify energy saving of 15%, or even to 30%. The achievable energy savings of 48% for the apartment buildings is very high for an energy audit. Data really does show just how badly performing some apartment buildings are in terms of their energy usage. The good news is that data shows apartments can see real reductions in their energy usage through simple upgrades.

Cost savings

Somewhat surprisingly the audits discovered all 15 sites were paying too much for electricity.

This was due to a number of reasons including sub-optimal retail rates, network tariffs, and metering configurations.

In regards to retail rates; sites could save 10% to 15% off electricity costs by simply picking up the phone and moving off default tariffs onto a market contract. Across all 15 sites this would save $26k per year.

In regards to metering configurations audits found that many sites could reduce their electriicty bills by between 10% and 25% by installing a smart meter and moving from a flate rate ‘all-time’ tariff to a time of use tariff. Savings could be achieved in buildings were a significant proportion of equipment switches on during the night during cheaper off-peak periods. For example at some sites the majority of car park lihgting and interior lobby lighting switches on at night. Whether or not a site will see cost savings by installing a smart meter is highly site specific and should be assessed by an energy audit.

Lighting – The biggest user of common area electricity

For the 15 sites ligting was the biggest energy user. This is largely due to the fact that no sites had a central air conditioning system (i.e. chiller, pumps and air handling units). Only one of the sites had a heated pool.

Car park lighting was found to be the biggest electricity user in the apartment buildings, accounting for 46% of total electricity usage across all 15 sites. The good news is cost effective options are available that can dramatically reduce car park lighting energy usage.

The biggest source of energy wastage was found to be car park lighting over car spaces running 24 hours a day, in some cases lighting over car spaces was recorded to be well over required levels. De-lamping tubes from these fittings, replacing the entire fitting with a new high efficiency fitting were found to provide good energy savings. Installing motion sensors to control lights, or installing T8 to T5 converters or LED tubes into fittings were also found to provide good energy savings, hoever these measures may have potential safety and compliance issues

One intersting outcome of the site audits was that some sites had switched off lighting in car parks and interior lobbies and stairwells during the day to reduce energy usage. Due to this it appeared in some areas that light levels had falled below australian standards. It is important to balance the desire for energy savings with the needs and safety of occupants. And of course it is imperative to ensure lighting complies with building codes and australian standards.