Our Energy Performance

eCubed
05 May 2015

As part of our in-house energy monitoring we track the consumption of each of our offices, year on year.  We’re doing pretty well, with both offices showing continued reduction in energy use over the last three years. 

The graph above shows the total energy use of each of our offices (normalised by floor area) over the last four years.

The Wellington office, which is a tenancy in an office building, is sitting at 55 kWh/m2/yr.  As a benchmark the NABERSNZ energy rating tool estimates the average office tenancy would use around 100 kWh/m2/yr.   The Auckland office is at 83 kWh/m2/yr, compared to the average of 200 kWh/m2/yr (again, according to NABERSNZ benchmarks for a whole building).

We should point out that some of the changes over the years are due to staffing numbers (between 2011/12 we had a staff increase in Auckland, and a sub-tenant moved out of the Wellington office between 2012/13) though even on an FTE basis we’re still getting a downward trend.

Ultimately we’re hoping to get each office down to around 50 kWh/m2/yr.  We’ve reached the point where we’re starting to rely on behaviour change to reduce energy consumption further – which is also the hardest part to put into practice!

Some notes:

  • We’ve graphed kWh/m2/yr in order to normalise each office’s energy use and compare with benchmarks.  kWh Per FTE figures are 169 and 79 for Auckland and Wellington respectively.
  • Neither office has gas or air conditioning, both relying on plug-in heating in winter and fans in the Auckland summer.
  • A kWh (kilowatt-hour) is the standard unit electricity is sold in.  It equates to around 25 cents or 3,600,000 Joules of energy, what a 1 kW appliance (say, a one bar heater) would use if left on for an hour.  Your consumption in kWh is on the reverse side of the power bill – which is why engineers always skip the first page!