Does Australia Need a Home Sustainability Rating System? 18

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Monday, May 4th, 2015
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Cars, appliances, and televisions have long carried a “window sticker” that cites performance data. Is it time for new homes to carry something similar that addresses sustainability?

Homes have a collection of systems, some of which have these performance labels, but most homes do not. Is it possible to create one for the home itself, and would it be useful for home buyers?

First, it is important to outline what constitutes a sustainable house. The Australian Government’s ESD Design Guide (2007) defines it as “using, conserving and enhancing the community’s resources so that ecological processes, on which life depends, are maintained.”

Building industry stakeholders have more specific ideas, with requirements for energy, greenhouse gasses, and water performance. As Suzanne Tombourou, executive officer of the Australian Sustainable Built Environment Council, has noted, the implementation of these ideas “would allow the sustainability approach to be broadened beyond ‘low carbon’ homes to ‘low impact’ homes, giving potential buyers a much clearer picture of a building’s environmental performance and lifetime running costs.”

Building industry stakeholders also stated that they wanted requirements harmonised “across Australia so that assessment, implementation and compliance were uniform across the nation.”

Other stakeholders might opt for additional or different measurements, such as energy source, energy embodied in materials, amount of waste generated in construction and over time, durability of materials, resilience, adaptability, land use and siting, and so on. However, a comprehensive label could be cumbersome in practice.

“At this point there has also been very limited uptake of rating schemes that benchmark housing across a wide range of sustainability indicators,” wrote Dr Stephen White, ASBEC’s Sustainable Housing Task Group chair, CSIRO’s Energy for Buildings manager, and program leader for ‘Engaged Communities’ at the Low Carbon Living Cooperative Research Centre.

A variety of rating systems already exist, with a focus on different elements of building design and performance, such as indoor air quality, universal design, and so on. Presumably, those benchmarks could be combined to give the homebuyer a more comprehensive picture.

One important question, according to White, is whether multiple elements of sustainability should be considered in a single scheme, or separately.

“On the one hand, including all elements in one rating may dilute the attention required for individual elements,” he said. “On the other hand, multiple schemes to cover each element may become complex and create rating fatigue.”

Here’s an example of a window sticker from Postgreen Homes, a builder in the US:

Sustainable -

The energy data for this sticker comes from HERS, the Home Energy Rating System, which uses construction specifications to estimate energy consumption. After the house is built, a certified rater performs a blower door test, duct leakage test, combustion analysis, and infrared camera inspection for heat loss.

Is that enough information for a homeowner or homebuyer? What about seeing performance data for the average year’s coldest day, hottest day, and average day? Obviously this idea requires that data be regionally optimized to be accurate, as local conditions have an impact on both house performance and the sustainability of available resources.

Yet, White noted, “it is yet to be seen if it’s possible to have a single one-size-fits-all rating system for sustainable housing.”

As for cost, does a sustainable home have to cost more than a standard home? A “window sticker” can also show that the adoption of more sustainable features makes sense, as studies show that sustainable homes do not necessarily cost more than those built to code minimum, and will be cheaper to run.

According to White, a Sustainability House study that compared about 4.5 million alternative house designs (each dot in the graph below representing a compliant design) showed that an energy efficient home can cost less to build than the “deemed to comply” design.

Sustainable - 1

However, noted White, the designer must have the flexibility to design for optimal energy efficiency.

“If a fixed design is provided to the designer with the instruction to ‘make it compliant’, then the designer loses freedom to make appropriate trade-offs and is forced just to add compliance features (e.g. insulation, double glazing etc), with resulting increase in cost,” he said. “The key learning is that flexible rating schemes allow the construction industry to find the best solutions.”

While many metrics are easy to measure, the real wild card in the whole scheme is those who wind up living in the houses.

“While schemes that focus on house construction quality are important, it appears that additional work is required to focus on occupant behaviour,” White said.

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18
  1. Tobin

    While the answer is use, the key to the effectiveness of any such schemes will be a versatile and nuanced system that is capable of catering to the highly disparate climate regions of a country as geographically vast as Australia.

  2. Steven Huxham

    Yes we do…..we could have a similar system to that on White goods … a Star system where we concentrate on the buildings energy consumption, regeneration, sustainability and longevity of building and material performance. This thought pattern is not only for new builds but can also be applied to our excising housing/building stock, (massive energy sink hole) which could be measured as part of the Building Reg's for compliance to major renovation works or home improvements……

    There is a lot to discuss here as its not just one silver bullet and we have a solution…… many 'energy conscious' developing country's have gone through the same pit falls, such as leaky buildings in NZ, massive condensation and mold problems in the UK and the US and these problems are getting more prevalent here in Australia…. there are some easy common sense step changes we can incorporate now and then build upon, but the end goal must be that we have to look at the total building performance to get, positive and measurable results. Which then gets us 'Sustainable Housing' stock for the future.

    Lets not just concentrate on building affordable housing but lets think about "affordable to live in h

  3. Nigel Howard

    Probably – BUT it is MUCH harder than commercial – BREEAM Homes failed twice even with Saatchi and Saatchi advising on the second version before ECOHOMES succeeded. LEED still struggles to really get LEED H off of the ground.

    The market scale is two orders of magnitude larger – so the magic number of 5% of the market engaged(to reach the tipping point of a sustained rating tool or any new product or service come to that) is MUCH harder. It is also an industry with much tighter margins for profitability and if you engage a major housebuilder, the rest will automatically oppose and marginalise this achievement. AND don't expect to roll it out with the same Commercial buildings business model – it has to be simpler – it has to be based on pattern book housing that is replicated many times to be commercially viable (so that the fee per house can be very low). AND it has to leverage the housebuilders own marketing machinery to have any chance of reaching the homebuyer in sufficient quantities. It needs to be part of the judging criteria for "The Block" to get mass market awareness.

    And then there's the HIA who already have some form of scheme and will lobby hard for minimal differentiation of the market or anything that adds cost (not that you need to add cost to have much more sustainable homes).

    Lastly, of all rating tools, this is one that really does need government support and endorsement and some regulatory stick to leverage the rating systems carrots out of the ground.

    Apart from that it should be easy 😉 and if you want a real challenge try existing housing!!!

  4. Howard Elston

    Yes we do. I think a good home sustainability rating system would work in the same way as a good education system in that it is important to have standards against which performance can be judged. Of course, as noted in the article, the devil is in the detail. What exactly are the required outcomes? Should there be one overall standard (ie one big exam to judge performance) or a collection of standards that can be used to give a clearer picture of how the house performs (series of assessment tasks). Giving designers and builders freedom in how they meet the standard is essential as this should encourage innovative and cost effective ways to reach the desired endpoint. It's also important to move beyond a simple star rating system. When faced with similar priced homes, one a "stock standard" and one built with embedded sustainability features, I'm assuming a buyer would go for the sustainable home once they saw the lower operating costs quoted on a detailed sustainability rating sticker. Would this be enough to drive more builders towards sustainability as customer demand for lower operating cost homes increased?

  5. Fiona McKenzie

    We could adopt or at the very least reward the application of the Passive House Standard. It is already established. It can't be compromised. It is run by an institute steeped in building physics. It deals with health, comfort, low energy use, climate change, condensation and mould. NYC has mentioned it in its plans to reduce emissions. "One City Built to Last". Brussels has mandated it.

    Climate Change is our most pressing sustainability issue.

    Cost in Australia? Cost per sqm is more. Ongoing cost to the world and the homeowner is less. Oh, hang on a minute, Cost per sqm?

    How about smaller homes? Australia already has the biggest in the world. How about we build smaller nicer homes with a better quality of living and then the cost is the same?

  6. Keal Wilson

    I don't think there would be so much need to go all the way to an international standard such as BREEAM or LEED, whilst they are very in depth I think you'd have trouble with the cost/practicality in the mass residential market, and whether they would properly apply to our climate and energy costs could be another thing. Being registered in the UK as a Domestic Energy Assessor and in Aust. as a Green Loan Home Sustainability assessor the DEA scheme in the UK is in depth enough to give a good understanding of how efficient the property is, the green loan assessment was a bit shallow. Australia already has the NABERS system which has standards for homes, what would be required is maybe some tinkering to the ratings for mass market uptake and some council or state government regulation to require the assessment if a property is to be sold or every 2 or so years for rentals. Could create a few jobs.

  7. Mihail Stankov

    Yes we do. A person spending the amount of half a million and paying it back in the next 25 years has the right to be able to compare the cheap housing with the more expensive but long term better designed one.

  8. Max Deuble

    We definitely do and quickly. I believe there will be a market for it but there are a few barriers within the residential construction industry that will make it hard to develop a holistic tool. For instance, the cost of GECA- or GreenTag-certified materials and furniture for houses is unrealistic; trying to find where your materials are being sourced from is also difficult.

    There are some current green "home" standards, but the current Housing Industry Association's GreenSmart or the EnviroDevelopment green building standards (which I believe focus more on the construction side rather than the performance), need to be much more comprehensive in much the same way as Green Star is for commercial buildings. Furthermore, often there are restrictions posed by Council Development Planning rules that may make achieving these aspirational goals difficult.

    • Max Deuble

      Yes we do have NatHERS and BASIX (for NSW) but these do not go into the depth that is required to convert the majority of our new and existing housing stock into green homes. From what I understand, these are based on thermal performance/cooling and heating loads derived from aspect, orientation, glazing, and other various building construction materials. In fact, I still remember everyone raving about one season of "The Block" marketing that their apartments achieved 8 star NatHERS ratings. However, I found it funny that all the contestants still installed radiant heaters and other energy-intensive equipment, which will increase the apartments' energy usage; regardless of getting 8 star NatHERS, you can still make your home very energy inefficient unless you take into account the occupant's behaviour and energy end-use.

      The NABERS rating for homes, I've found, is not nearly as good as its commercial counterpart. I think a lot more work could and should be done into making the NABERS Home rating much more equitable across the wide range of housing types, e.g. standalone houses and single dwelling apartments can often be discounted in these ratings if the benchmarks are based on 4 person family homes.

      Finally, the new Green Star Design and As Built tool, at least from the GBCA's perspective, can be and is encouraged for use in standalone dwelling constructions, however, the tool is mainly based on commercial office benchmarks which will make it hard for simple homes to achieve any level of Green Star certification. But, that being said, the GBCA does offer customising this tool for residential houses wishing to become Green Star certified.

  9. Nathan Peart

    Yes – I think a more inclusive sustainability system would be good, but on a voluntary basis only. The BCA requirements focus soley on the building fabric. As Max mentioned the NatHERS assessments focus on heating and cooling of a house only. It does not matter how you heat or cool your house, you can have a great star rating but still have inefficient appliances so you end up with the situation in The Block.

    I am a NatHERS assessor and carry out assessments Australia wide including Basix assessments in NSW. In general I think the Basix system in NSW is a good tool to get a holistic approach to a wider concept of sustainability, that importantly engages the householder in thinking about the sustainability aspects that they want to include in their new dwelling or renovation.

    When carrying out asessments under NatHERS alone, more often than not, the question is how to comply with the least cost and effort. This will not be removed from the market place, due to the competitive pressures on builders.

    But it would be good to have a sustainability tool, for example a beefed up Basix, that clients who want a sustainable house, rather than one that just meets the minimum energy efficiency requirements, could use.

  10. Daniel Wurm

    what a great question. We all readyhave an energy rating system that does work, albiet is somewhat a very low standard because we can do better. However where it fails is with the as-built. If only we had control over what was actually built, then we could verify what standard our building stock actually was and not the potential of as-design.

    • Nigel Howard

      With respect, you are wrong – from 1998 onwards, BREEAM and then ECOHOMES included embodied energy as fossil fuel depletion together with about 12 other environmental impact categories weighted for significance by a series of UK stakeholder groups, resulting in an A,B,C rating for every element of a building. I know this for a fact because I put it there as Director for the Centre for Sustainable Construction. This content has been improved on since with now 5 levels of rating for each element and still including fossil fuel depletion.

      LEED and Green Star have credits and pilot credits for LCA content that include fossil fuel depletion and GWP (which in any event correlates pretty well with embodied energy). (As VP for USGBC, I also pioneered LCA into LEED but this was not completed before moving to Australia).

      Lastly embodied energy is a rather strange concept unless it is defined in a way that has a consequence – i.e. it is better defined as fossil fuel depletion, because consuming renewable energy as you do with kiln dried wood fired from wood wastes does not have the consequences of consuming fossil fuels.

      But to your point about mud brick houses – yes they deserve it

  11. Max Deuble

    The new Green Star Design & As Built tool (which was released in October 2014) now includes credits for LCA focusing on the life cycle impacts of the proposed building's materials

  12. Daniel Wurm

    Thank-you Max and Nigel. I was referring to Australian rating systems for homes, which is what this discussion thread is about. BREEAM and ECOHOMES are from the UK; and Green Star is for commercial, offices etc. I would love to see a system that combines the best of all the above, and is adapted to the Australian market.

  13. Fiona McKenzie

    Just reread the article.
    Noting that the articled says about a scheme in the US: "After the house is built, a certified rater performs a blower door test, duct leakage test, combustion analysis, and infrared camera inspection for heat loss.
    Is that enough information for a homeowner or homebuyer? What about seeing performance data for the average year’s coldest day, hottest day, and average day?" In my view energy use must be assessed and modelled in homes. It must be done so independently of other sustainability outcomes such as carbon utilised in fabrication of materials, or transport costs, etc. In Australia we don't even get the basic energy use issue right. We don't properly model it. We don't properly test buildings after construction. In answer to the question Steve Hansen puts, regardless of what else you do, energy use for the life of the building needs to be addressed, urgently.

  14. Chris Walker

    It appears most are in agreement that a rating system of some kind is required.

    Currently, the BCA requires an assessment of the thermal performance of a dwelling’s building fabric. This process obviously only looks at the impacts of good and poor thermally performing construction materials as opposed to their origins or sustainability credentials (as noted). Local Governments have also developed/adopted tools that sets benchmarks for the building services and operational impacts of a development. Then there is the whole suit of other tools that have been adapted to the residential market listed in the comments above.

    For a rating system to be relevant and successful it must be adopted by the market and used to drive further sustainably motivated outcomes. A nationally based tool (adapted to local conditions) would allow residential developments to be assessed in both their construction and operation, and would allow mandatory disclosure for dwellings to be adopted nationally. The market would then drive sustainable transformation. Ongoing utility burden, sell-ability/rent-ability, market edge, community image and the desire for best practice will drive the residential building market in the same way Green Star and NABERS has done for other building sectors.

    We have shown the residential construction industry and skilled labour force can handle the recent shifts in building performance standards at no negative impact to housing supply or affordability. Now it is time for the next leap.

  15. Chris van der Pol

    Yes, we need visionary thinking and governance to drive sustainability in our housing, but let's not forget the basics.People live in houses.Those people will make the best housing choice that they can for their circumstances in a housing market that, by world standards, is relatively expensive. So the greatest driver of sustainability will remain, for most people, their hip pocket. This is an incredibly powerful tool, and a great opportunity for communication and education. The more effectively we can communicate a dwelling's up-front and ongoing costs and benefits, the greater the capacity to seamlessly implement improvements in sustainability, occupant health and comfort into our housing market.

  16. Darren ODea

    Release the tax payers CSIRO calculation engine to the public, and alow the market a say? Not a big follow of Adam Smith's invisible hand, but surely a creative market based response would benefit this process rather than maintain the status 'inadequate' quo?