Blurred city lights. Source:

How much impact might savings “within the walls” have?

In a recent post I commented:

If developers aren’t prioritising sustainability due to a perceived lack of market demand, and owners corporations’ focus is elsewhere, where else can efficiencies be gained? What about what happens “within the walls” of the apartments themselves?

While the individual savings might be small, the cumulative benefits might be significant. Just how significant is unclear, however. So it’s hard to judge just what sort of impact energy efficiency measures across a medium- or high-density residential complex would be. I did a bit of digging but couldn’t find readily available stats. Are savings in this context just going to be a “band-aid” solution? Or can it make a significant contribution?

Let’s assume, for a moment, that the cumulative effect is significant enough to warrant attention.

Ahh, assumptions. We have to make them sometimes to get moving, but it’s always best to close the loop, through research, if we can.

I spent a little bit of time the other day looking into this, seeing if I could source stats or research that examine the difference in energy consumption in a medium- and/or high-density residential environment (e.g. apartments) versus low-density (e.g. houses), and found some interesting tidbits…

One thing that’s clear is that there doesn’t seem to be a huge amount of publicly accessible information (i.e. accessible from a cursory Google search) on this particular comparison. Even so, there were some interesting stats that emerged, including:

“Taking into consideration electricity and natural gas used by apartments and by common area equipment the hi-rise apartment has 86% higher per capita greenhouse gas emissions.” (Source: Multi Unit Residential Buildings Energy & Peak Demand Study, 2005 cited in Energy Smart Strata (PDF))

However, Australian Bureau of Statistics reports that:

“Households living in separate houses had significantly higher energy costs per week than other types of dwellings. The average energy costs among separate houses was $109 per week, while for semi-detached, row or terrace houses or townhouses it was $70 per week and for flats, units or apartments it was $59 per week. Both expenditure on dwelling energy and fuel for vehicles, and units consumed of electricity and mains gas followed similar patterns according to dwelling type.” (Source: Household Energy Consumption Survey, Australia: Summary of Results, 2012)

So, if highrise apartments have higher emissions/consumption, yet householders in apartments pay less for energy than equivalent stand-alone households, what’s going on? What’s causing this counter-intuitive result?

One hypothesis is that common area electricity usage is a significant driver of these emissions (and, by extension, energy usage). This view is supported by a 2010 article in the Fifth Estate:

“According to a NSW Energy Australia study, a highrise apartment uses 30 per cent more power than a typical detached house. Much of this is in the common areas such as foyers and car parks where lights are often inefficient and are left on night and day.”

So, based on this (admittedly limited) finding, we could extrapolate and surmise that the actual opportunities for savings “within the walls” is not only limited for the resident/occupant, but that this may not represent significant savings opportunities for other interested third parties wishing to capitalise on aggregate energy savings.

That is to say, even though a) a majority of people live in urban environments, and b) a significant portion of those live in high-density, that savings at the individual household level wouldn’t be an immediate priority for those seeking energy reductions.

Load shifting may still be desirable in these environments, however. So this may be a more fruitful avenue of inquiry if we wish to tap into this under-served market to influence energy consumption behaviours to achieve outcomes that are also valuable to third-parties (such as utility companies).

I’m planning on diving a bit more into the research that’s available, to validate this assumption and get a better understanding. I’d be interested to know if anyone has found any other good studies that compare energy usage across contexts, and/or look at energy savings opportunities across these contexts? And always interested in thoughts on the above hypotheses related to the potential market/customers for products and services that target behaviour change in this context?

Feature image credit.

Also published on Medium.