Human settlements

Local greenhouse action

AGO-CSIRO Greenhouse Efficient Design

AGO-CSIRO Greenhouse Efficient Design
S.N. Tucker, P.W. Newton, A. E. Delsante, M.D. Ambrose, D.R. Johnston, S. Allen, B. Rasheed and T.R. Remmers
for Australian Greenhouse Office, © CSIRO 2002, June 2002

Executive summary

Objective

The objective of this project was to achieve a 60% improvement in annual operating energy efficiency (heating and cooling costs) in project homes built at Lend Lease Development's North Lakes Master Planned community as a result of shifts in design practice among merchant builders in South East Queensland. The principal approach was to lift energy star ratings from under 1.5 to at least 3.5 stars, representing a significant contribution to the potential for reducing of CO2 emissions, estimated to be up to 5 tonnes per year for a contemporary 3-bedroom project house with solar hot water.

This shift could subsequently be extended throughout Pine Rivers Shire, South East Queensland and Queensland in general via demonstration activities at a Concept House, on-going workshops and continuing education by the Environmental Protection Authority of Queensland and Faculty of the Built Environment at the Queensland University of Technology. The impact of changes in approach to energy efficiency of houses is expected to be high in Queensland, a state which currently lacks a house energy ratings scheme, and with significant population growth and new house construction forecast over the next decade, where new house designs exhibit major scope for improvement.

Project

The project consisted of:

Workshops

The workshops were designed to:

The prime target groups were Lend Lease Development builders, members of the Building Designers' Association of Queensland and HIA members. Two workshops were held on 29 and 30 October 2001 respectively at the North Lakes Community Activity Centre:

The workshops were designed to consist of short, sharp presentations plus interactive sessions to reinforce the principles and practices outlined in the presentations. It was originally proposed that the forthcoming building energy code for South East Queensland be addressed at the workshops. The proposed code was withdrawn and so did not feature in the workshops. The workshops were successful in that those who attended found the presentation and content most relevant to the topic, but the numbers attending (particularly the builders) were somewhat disappointing.

Findings

The following points are worth considering for future workshops:

Concept house

The objective was to provide guidance in creating a concept house to be constructed at North Lakes with design inputs from CSIRO, Environmental Protection Authority of Queensland and leading Brisbane designers embodying next-generation materials, design features and appliances which demonstrates affordable energy efficient housing (5.0 star minimum) and provides a location for a range of community awareness-raising activities by Lend Lease Developments in addition to the visits by house-seekers to the North Lakes Display Village. The idea here was to provide the development with a unique showcase of leading edge concepts.

Client

Wesley Mission took on the role of "client/owner" in developing three concept houses (the project objective was only one) and managing the construction and marketing of the houses as a means of generating funds for charity and community work. Wesley Mission was fully committed to the energy efficiency and sustainability concepts of this project and was responsible for the procurement of labour and materials for the houses in accordance with the concepts, specifications and approved designs. Its participation in the project was invaluable and made it possible for the concept to become a reality.

The Concept Houses were built at the North Lakes site adjacent to the second display village and progressed more slowly than anticipated due to lengthy negotiations with prospective builders. The desired characteristics were specified and ongoing discussions with HIA and Lend Lease Developments continued to establish the scope and expectations. The houses are available for public inspection and education for the duration of the term of the second display village.

The concept houses were constructed early in 2002, and opened in May 2002 by the Queensland Environment Minister (Dean Wells), Queensland Families Minister (Judy Spence) and Wesley Mission Superintendent (Rev Dr Gordon Moyes) together with Lions AFL footballer Shaun Hart. The Wesley Mission expects to raise $500,000 from the sale of the houses at the conclusion of the display period.

Environmental considerations

While the final energy efficiency of the houses is far above that of almost all of the other houses built at North lakes, the concept houses still fall well short of the ideal environmentally friendly house as first proposed. Practicalities and costs tend to restrict the implemented options to the mandatory and those which are cost effective.

Overall, the parties involved in the project were enthusiastic in pursuing an environmentally innovative set of houses. The three builders involved have come with very different levels of experience with environmental design, with Eco Dezign being one of the experts in the area, while Roberts have little experience with this design philosophy, but see this project as a valuable way to develop their skills in energy and environmental design.

The location next to the second display village should ensure that there will be a constant stream of visitors who will see high performing houses which look little different from the other display houses. The concept house approach appears to be one method of focussing attention on an environmentally friendly house and demonstrating its acceptability to potential owners of new houses.

The base requirement for each house is that they achieve the PATHE GreenSmart guidelines as established by the HIA. This covers several environmental aspects including energy consumption, water conservation and waste reduction.

Additional features

In addition to the GreenSmart requirements each house has been required to achieve a higher degree of environmental design in three specific areas (one for each house).

The Water Smart house focussed on

The Energy Smart house focussed on

The Technology Smart house focussed on

Initial energy analysis was undertaken using the BERS software to determine the energy rating of each house, all of which readily achieved a 5-star rating as required.

Surveys

By conducting two surveys the study sought to identify key factors and measure the extent of any change in these factors. Specifically the survey instrument addressed the issues of: knowledge of energy design principles in housing, attitude to environment and greenhouse emissions and extent of application of energy / greenhouse principles to design / construction of new project houses amongst designers and builders in South East Queensland, and specifically those involved in the North Lakes development.

The surveys appear to indicate trends toward the industry embracing best practice in ensuring energy efficiency / reduced green house emissions. The momentum of this trend has certainly increased since local government has begun adopting energy efficiency codes as part of the approval process. Statistically, this analysis has not been able to demonstrate a conclusive indication of these trends but there clearly has been an indication of these trends evident in the responses received.

Survey process

The first sample for the survey was drawn from the member lists in South East Queensland of the Building Designers' Association of Queensland (BDAQ) and the Housing Industry Association (HIA). Agreements were reached with these organizations for them to assist in the distribution of the survey instrument; the BDAQ distributed the survey in their quarterly newsletter, the HIA distributed the form by email and the survey was sent by mail to builders and designers operating at North Lakes.

The first survey was conducted prior to the first workshop, which was eventually held on 29 and 30 October 2001. The initial group of survey forms was sent out on 25 May 2001, to be returned by 29 June 2001. Because of the delay in the workshops, survey forms were accepted up until the end of October 2001. The second survey was conducted in April 2002.

Due to the small size of the responses, (88 in total (59 from BDAQ and 29 from HIA) in the first survey and 47 in the second survey) the data presented below is based upon these two sets (first and second surveys) of data grouped together.

Responses

Respondents identified and acknowledged many significant issues they believed would affect the design of housing with respect to energy efficiency, and the lowering of greenhouse emissions. It is clear that more should be done to provide relevant information to help the industry to make informed decisions in the applications necessary to achieve these ends.

General knowledge as reflected in the survey results ranges from poor to cursory. Many misconceptions exist in the industry regarding best practice in greenhouse/energy efficient design. The responses indicate that a misconception exists regarding the cost premiums for greenhouse / energy efficient housing. The industry appears to reflect the same public notion that greenhouse/ energy efficient housing is at least 10% more expensive than conventional housing. Those builders who have built a high percentage of greenhouse/ energy efficient housing indicate that the figure is closer to 5% more expensive despite the house energy assessments suggesting that the minimum costs are much less.

Education is perceived as a means to expand public and industry knowledge and attitudes toward greenhouse/ energy efficient housing, thereby increasing demand. Respondents also encourage government subsidisation of education of public and industry practitioners to promote greater demand for greenhouse/ energy efficient housing. Affordability of energy efficiency features of houses should be encouraged, and is seen to be the domain of tax incentives, utility rebates, and reduced-rates incentives.

Practical, easy methods of assessing the performance of a house at the design stage were of great concern to many respondents. Further research into the preferences of respondents for the current trend of prescriptive methods of compliance (deemed-to-comply) over detailed (computer) analysis would be a logical avenue of future research to determine the role of both in achieving energy efficient houses.

Self-certification / deemed-to-comply, prescriptive methods of assessment are practical, easy, and an inexpensive means for builders / designers to assess compliance of their designs. However such compliance methods are limited in assessing a variety of design solutions, leaving more expensive, third-party (accredited agent) assessments as the only means of ensuring compliance to standards of designs with other than 'acceptable' code solutions.

There is a strong indication that since respondents clearly rated heating and cooling as significant issues to address in the design of housing with respect to energy efficiency, more should be done to provide relevant information for the public, and industry alike to make informed decisions.

Energy assessment of houses

The energy assessments of individual houses were designed to compare the energy performance (in terms of energy ratings) of houses built in the first stages of development with the performance of houses built in the second stage. This approach acts as a simple means of assessing awareness of the importance of energy efficiency in houses at different points in time. The assessments expand upon the original Office of Sustainable Energy assessments of the energy efficiency of houses in the first display village using BERS to consider what options would improve the energy efficiency.

Energy assessment tasks

The following tasks were undertaken in this part of the study:

Assessment tools

The preferred assessment tool for energy efficiency and star ratings in Queensland is the Building Energy Rating Scheme (BERS). BERS uses the NatHERS calculation engine. The houses chosen to be assessed from the display villages were all those houses which could be accessed with complete plans and other information. The houses from the non-display village sites were randomly selected from the plans submitted to the North Lakes developer for approval. The additional software tool (ART) described above to determine minimum-cost solutions for achieving 3.5 star ratings was also utilised.

Energy efficiency ratings

Most of the houses (78.6%) in the first display village had star ratings of 1.0 or less, with a few exceptional houses having star ratings of 3.0 and 4.0. The wide range of star ratings may reflect the different purposes assumed by the builders for display village houses. Some of the houses may have additional energy-saving features which were not shown on the plans but it is unlikely that, other than the three houses with star ratings of 3.0 or more, any of the remaining houses would have reached anywhere near a 3.0 star rating even with the undocumented features.

The sample of 24 houses constructed in the last year within the Pine Rivers Shire (excluding the North Lakes project) and assessed using BERS were all below 2-star rating with an average just below 1 star. The houses in the North Lakes which are contemporary with the houses in the Pine Rivers Shire were assessed to have slightly better energy performance but well less than that desirable of at least 3.5 stars. Second stage display village dwellings improved their energy efficiency slightly (around 11% better), although still maintaining a low average star rating a little above 1 star.

Improvement options and costs

In the first study by the Office of Sustainable Energy, selected improvements were added to each of the houses and the improvement in star rating noted. A judgment was made as to what sequence the improvements should be added, based on effectiveness in improvement of the star rating. The improvements were added until the star rating exceeded 3.5. Adding ceiling insulation to R2.5 was the most common, occurring in 11 out of 14 houses assessed. The next most common was RFL wall insulation (which provides a total thermal resistance in brick veneer walls of approximately R1.5). Window treatments were also very common, using one or both of window tinting and reflective windows. Awnings and pergolas and thicker ceiling and wall insulation were not on the list of available improvements for this first attempt by the Office of Sustainable Energy to identify the most effective improvements, but were on the list done for the non-display village houses.

The non-display village houses in the first stage were star-rated using the CSIRO developed Automatic Rating Tool (ART). The effectiveness of improvements depended on the cost of the improvement, not just the savings in energy. In contrast with the distribution of the star ratings for the display village houses, the non-display village houses did not have any significant spread in ratings. All ratings were between 0.5 and 1.5 stars. In addition, the ART tried to find the least-cost combination of improvements to achieve the target star rating (3.5). There were two houses which could not get to a star rating of 3.5 with any combination of options available. For less than $2000, the star ratings of 45% of the houses could be improved to 3.5 stars. More than $5000 was required for only two of the houses to achieve the same results. The average cost per house for the whole group was $3015. Thus, the cost to achieve 3.5 stars from an average star rating of about 1.0 star is a relatively small percentage (all less than 5%) of the cost of the houses (excluding land).

Also calculable was the cost-effectiveness of the improvements as measured in terms of MJ saved per dollar invested. Ceiling insulation at around 19 MJ/$ is by far the most cost-effective option and this option occurred very commonly as a means of raising the star rating. The next most cost-effective improvement was RFL wall insulation (with a value just over 3 MJ/$), which can only be installed at the time of construction. Awnings and tinting windows also have a cost-effectiveness ratio of about 3 MJ/$.

Results

There is a trend to house which are more energy efficient with the prospect that the remaining houses to be built in North Lakes will be much improved on the first houses built there but it is a slow process to achieve an average of 3.5 star ratings without regulation of some kind.

Lessons learnt from the assessment of the various groups of houses include:

Only a small reduction has been achieved in greenhouse gas emissions from the first stage display village to the second stage display village of about 124kg/dwelling/year.

Outcomes

The expected outcomes included a reduction in greenhouse gas emissions, a change in design practices and a change in attitudes in house buyers. The study was most successful in demonstrating that an integrated design solution could produce an attractive house which was energy efficient and at little additional cost as shown by the concept houses, gaining an understanding of attitudes to energy efficiency in houses, promoting energy efficiency by the construction of three concept houses and providing practical workshops for designers and builders of houses in the region.

The North Lakes project builders do use design software effectively when it is required to generate 3.5 star rated house plans but the demand is not there to encourage such evaluations on each and every house. The builders' pragmatic attitudes will only change slowly until there is an impetus for 100% of houses to be energy efficient.

There is a need for appropriate information packages being developed and marketed to house buyers by the Environment Protection Agency to convey the latest knowledge about energy and greenhouse efficient housing but the effectiveness of any campaign would be difficult to judge if it was not conducted in conjunction with a move to all houses being at least 3.5 stars.

Reduction in greenhouse gas emissions

A target of a reduction of 110,320 tonnes greenhouse gas reductions over 10 years was very ambitious and included reduction in embodied energy, vehicle kilometres travelled and operating energy.

Greenhouse gas emissions resulting from mandatory rating of dwelling to 3.5 stars for heating/cooling requirements only were estimated to be around 1 tonne/dwelling/year, far less than the expected 5 tones per year for all aspects of energy related green house gas reductions. A mandatory 3.5 star rating can achieve a 60% reduction in greenhouse gas emissions due to heating and cooling requirements.

The study showed that a slight increase in embodied energy was necessary to gain the required reductions in heating and cooling for the houses.

Measurable shift in attitudes, knowledge and practices of North Lakes project homes designers and builders

The attendees at the workshops showed that they understood the key principles of energy efficiency as did the respondents to the questionnaire so the requirement that all workshop participants recall 90% of key principles was well satisfied.

Those at the workshop indicated that a quick and simple tool for checking the energy efficiency of a proposed design would be beneficial before they obtained any required formal approval that the design met the regulatory or desired standard. While many of the of workshop participants use BERS/NatHERS in their design and building of project home, the proportion of those who do is well below the target of 70%. Any shift to improved energy efficiency and a tool to assess such performance would be consumer or regulation driven.

Not all the North Lakes builders attended the workshops because the impending regulations were scrapped although the designers still showed considerable interest (until the date of the workshop was changed). The expected 90% of North Lakes project home designers and builders attending the workshops was not achieved.

The surveys indicated that the knowledge to improve the energy efficiency is available to the industry from a variety of sources but the incentive to utilize this information in practice is not, partly because of incorrect perceptions of the cost of energy efficiency and lack of regulation. If the developers of North Lakes were to make 3.5 stars mandatory for all new houses, there would be little difficulty in designers and builders meeting the challenge.

Measurable shift in attitudes, knowledge and behaviour of North Lakes project home buyers

Because the Office of Sustainable Energy was merged with the Environmental Protection Agency, and their educational activities curtailed, there was no action to derive baseline data on attitudes, knowledge and behaviour from representative sample of current residents of North Lakes Stage I.

Quantitative evaluation of the performance and costs of energy efficient improvements to the houses appears to be the only method of overcoming misconceptions of the relationship between cost and energy efficiency and the ease with which it is possible to design an energy efficient house (at least to a 3.5 star rating). The greatest difficulty is in disseminating such information and changing the buyers habits from focus on initial cost to life cycle cost and comfort in an energy efficient house.

Disclaimer

The Client makes use of this Report or any information provided by CSIRO in relation to the Consultancy Services at its own risk. CSIRO will not be responsible for the results of any actions taken by the Client or third parties on the basis of the information in this Report or other information provided by CSIRO nor for any errors or omissions that may be contained in this Report. CSIRO expressly disclaims any liability or responsibility to any person in respect of any thing done or omitted to be done by any person in reliance on this Report or any information provided.

© 2002 CSIRO To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO.

Please direct all enquiries to:
The Chief
CSIRO Building, Construction and Engineering
P.O. Box 56
Highett, Victoria 3190
AUSTRALIA

Acknowledgements

A large number of organizations and individuals were of assistance in undertaking this project. The researchers would particularly like to thank the following for their cooperation and willingness to participate:

Guy Gibson, Warren Thompson, Bob Smart, Chris Booth - Bovis Lend Lease Murray Vincent, Ray Jones - Environmental Protection Authority (Queensland) (originally Office of Sustainable Energy)
Rick Wiley - Housing Industry Association (Queensland)
Jillian Langsford-Smith - Queensland Master Builders' Association
Russell Brandon - Building Designers' Association of Queensland
James Ball - Wesley Mission
John Moynihan - Wisdom Consulting
Gary Choveaux and staff, Private Certification Unit - Pine Rivers Shire Council
Russ Ezzy - Eco Design Homes
David Hogan - Roberts Family Homes
Mark Zago - Markcon Homes
Liz Young - Australian Greenhouse Office

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