ENGG941 - Building Sustainability Analysis: Water, Energy Performance

This case study analyzes the building sustainability of a four-bedroom house, focusing on water performance, energy performance, and indoor thermal comfort using the Building Sustainability Index (BASIX) online tool. The analysis identifies shortcomings in the original design's BASIX score for ...Read More

Building Sustainability 1
ANALYSIS OF A BUILDING SUSTAINABILITY
By (Name)
Course
Professor’s name
University name
City, State
Date of submission

Building Sustainability 2
Table of content
Introduction........................................................................................................................................2
Objective..............................................................................................................................................2
Sub task 1: Building water performance........................................................................................3
Sub-Task 2: Building thermal comfort...........................................................................................8
Sub-Task 3: Building energy performance..................................................................................13
Discussion..........................................................................................................................................16
Recommendations............................................................................................................................16
References..........................................................................................................................................17
Appendix............................................................................................................................................18

Building Sustainability 3
Analysis of a building Sustainability
Introduction
Australia is one of the largest polluters in the world. Achieving net zero energy homes in
most countries like Australia has been a struggle with up to 1.5% greenhouse gas emission. A
report released by the Australian government shows that 23% of greenhouse gas emission is as a
result of the buildings energy demands (Iyer-Raniga & Wasiluk, 2007). Since 2002, there has
been restriction on water consumption as a strategy to counter drought conditions. Therefore, the
rapid enhancement of water and energy performance of the building sector can significantly add
to the environmental, social and economic benefits across the country, timely reduce global
energy use and promote environmental sustainability.
Objective
To analyze the 4 bedroom bungalow house case study to determine the building water
performance, energy performance, and indoor thermal comfort that are among the key steps
towards the sustainability of the built environment.
Sub task 1: Building water performance
Water consumption rate can be challenging to achieve in a home setting due to different
activities that require water to undertake. However, to achieve a sustainable design, it is a
requirement to fulfill the water consumption targets to help in saving water for future use. An
average family home is required to consume a target of 40%, however, this can vary depending
on different climatic conditions.

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Step 1
Calculate the BASIX score of “water” of the original case study building, and analyze the
reasons why the building fails to satisfy the BASIX PASS requirement
The BASIX report gives a score of 27% which is below the target of 40% water performance.
This means that the building sustainability in terms of water consumption is poor and cannot
sustain the test of time. Since the design has failed to meet the BASIX requirements, then it
means that there are a number of parameters that the builders did not take into consideration to
achieve a sustainable design. To comply with the BASIX standards, there are a number of
measures that have to be taken, but in this case study some of those measures were not fulfilled,
and that is what lead into the failure of the water performance of the building. Some of those
reasons include:
 Lack of rainwater tanks and storm water tanks in the design was a big failure to meet the
BASIX requirement.
 Use of WELS rated 3 star (>7.5 but <= 9 L/min) and 3 star toilet are not recommended
for the project to pass the BASIX test.
Figure 8: toilet cistern
 Indigenous species with low water use should have covered at least 80% of the site
instead of the garden covering a larger percentage considering that it uses more water
(Huizenga, et al., 2006).

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 The design lacked hot water recirculation system that would have helped to regulate the
hot water used throughout the development.
Step 2
Solutions appropriate to improve the water performance of the building to achieve BASIX
score of over 40%, 50% and 60%
 This building project will pass using WELS rated 7.5 - 9 litre/min showerhead, 4-star
toilets and 3-star basin and kitchen taps.
Figure 2: Showerhead
 Upgrading to 5 star tap ware achieves another 1% and 6-7.5 litre/min showerhead
achieves another 2%.

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Figure 3: tap
 Use rainwater tanks with 50 - 100% of roof draining to it connected to irrigation, clothes
washing and toilet flushing.
Figure 4: Rainwater tank
 Keep landscaped areas to a minimum and use low water plants such as natives
Figure 5: Landscaped area
Step 3
Estimate the likely investment required for your developed three solutions
To achieve the target for water performance, it definitely means that the cost of the investment
will increase with a significant amount of approximately $200 since the 5 star water fixtures are
very expensive.

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Step 4
Compare the three solutions you developed and discuss the advantages and disadvantages
of each solution.
Rainwater tanks are mainly used for storage of water that can be used in the wet areas such as
kitchen, toilet and the excess water can be used in irrigating the landscaped areas. The solutions I
have provided to improve the water performance is a kind of cycle or web whereby the
components are connected to each other to minimize on the water consumption. In this case we
have the primary component which is the rainwater tank which will supply water to the
household water fixtures such as the toilet and kitchen during rainy season when there is enough
water and there is basically no need to use water from Wollongong City Council. It therefore
means that, for water to be used sparingly in the bathroom, the showerhead should spray water of
around 8liters/min to save in consumption. On the other hand, the toilet should be 4 star, kitchen
and basin taps should be 3 star to help on the building water performances. The excess water due
to overflow can be used in the lawn areas and gardens.
Rainwater tank
Advantages
 Helps in storing runoff water from the roof area
 Helps in supplying indoor cold water taps
Disadvantages
 More building investment due to installation requirements and maintenance

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Keeping landscaped areas to minimum
Advantages
 Help in water conservation
Disadvantages
 Reduce the aesthetic of the environment
Water appliances
Advantages
 Reduce on water wastage
Disadvantages
 They are expensive hence increase the cost of construction
Sub-Task 2: Building thermal comfort
Achieving thermal comfort in a building is the most important requirement of a building
not only as a BASIX compliance but also it is a standard requirement in most countries. It is
important to take care of the cooling and heating loads to ensure that there is a balance of the
energy to help keep the indoor temperature warm. Thermal comfort can be achieved on account
of the location of the building, the size, orientation, form, glazing, ventilation and insulation.
The case study building failed to pass the BASIX comfort requirement due to a number of
reasons assessed in the energy performance of the building. Such failures include

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 Wall insulation: the internal wall shared between the two bedrooms and the garage lacks
additional insulation. This means that energy transfer co efficient will increase, more heat
will be lost from the bedrooms to the garage due to the difference in temperature
experienced in the two spaces.
 Wall insulation: the incorporation of the cavity wall in the design lacks additional
insulation which would have helped to reduce the U-value by 0.67, therefore, this
measure is a significant source of maintaining the balance between heat loss and heat
gain to achieve thermal comfort (Huizenga, et al., 2006). Significantly, the cavity wall
need more insulation, without further detail on insulation, it will mean that glazing will
be increased and this will eventually have a great impact on the windows, otherwise
double glazing is recommended to achieve a more thermal comfort design. Lack of more
insulation on the wall resulted in the design not complying with the BASIX requirement
leading to fail.
 Ceiling insulation, it is important to insulate the building at the ceiling level, but in this
case study, the ceiling did not account for the value of blanket and foil insulation to
improve the indoor temperature.
 Shading from structures: All windows (W1, W2, W3, and W4) lacked shading devices to
protect the indoor temperature from the direct solar radiation, this tampers with the
quality of the indoor temperature leading to poor thermal comfort. This resulted into
more heat transfer which gave a U-value of 6.7 and solar heat gain of 0.7. (Iyer-Raniga &
Wasiluk, 2007) Windows have a great impact on indoor temperature due to the long
wave radiation, solar radiation, and convention draft

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Figure 6: Window impact on the level of thermal comfort
 The recommended floor type for the design included a concrete slab on the ground, with
this type of floor, there will be more heat gain and loss due to the difference I
temperatures between the slab and concrete. This makes the concrete to loss more heat to
ground leaving the floor to be very cold and uncomfortable.
 In addition, the larger percentage of the concrete slab on the ground did not have an in-
slab heating system to help regulate the floor temperature while a small floor area of
35m2 was suspended from the ground and it was made of AAC panel on frame which
should be the other way round. The larger floor area can be suspended while the small
area can be on the ground.
Figure 7: Suspended floor slab

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 The wall type used on the external walls is a cavity brick with no additional insulation,
This reduce the potential of achieving thermal comfort, in addition, the internal walls
shared with garage is not recommended, unless the wall is installed with foil to regulate
the temperature.
On the other hand, there are certain strategies adopted in the design that helped to achieve
the building thermal comfort. These achievements include
 Glazing: this is an architectural feature that gives the occupants a direct connection to the
outdoor environment while at the same time reducing the energy lighting demands
 The glazed doors and windows used in the design help to reduce the total heating and
cooling loads. Glazing has drastically been reduced on the windows facing north since
there is always a high amount of solar radiation experienced on the north facing windows
(Huizenga, et al., 2006). In addition, the windows facing north have smaller sizes
compared to the windows on the east and west side where there is maximum glazing due
to short wave radiation encountered on these windows
Table 1: Summer comfort ratings for example glass types

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 Construction methods of the ceiling and roof type was a great move to help achieve
thermal comfort. Flat ceiling and a pitched roof or Pitched or Skillion roof/Raked ceiling
helps to increase the attic space for cooling the hot air that raises which eventually helps
to cool the indoor temperature for the occupants comfort.
Appropriate technical options to improve the thermal comfort of the case study building to PASS
the BASIX thermal comfort requirement
 Keep main living areas on the north side of the building to help maximize north faced
glazing.
 Position garage, laundry, and similar ‘service rooms’ to west and or south.
 20 - 40% of the buildings floor space should equal the amount of glazing – this is the
most economical.
 Windows are approximately 90% of a home’s heat gain and 50% of a home’s heat loss,
therefore aim to have: the majority of glazing on the north façade with up to 50% of the
façade glazed o Up to 15% of the east and west elevations glazed, and 10% of the
southern elevation glazed (Iyer-Raniga & Wasiluk, 2007).
 Fixed windows (not opening) tend to perform poorly particularly when placed high such
as in voids or at the top of gables.
 Thermal mass acts like a temperature battery and helps to reduce drastic changes in
temperature. Slab on ground with floor tiles and one or two internal brick walls in rooms
with large amounts of glazing can help with thermal comfort.
 450 - 900mm eaves (including gutter) are best for shading.

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 Large eaves or an alfresco over sliding doors can block winter sun from the opening
making the opening perform poorly due to heat loss.
 Insulate walls with R2.0 or R2.5 insulation and ceiling with R3.0 or R3.5 insulation and
install ‘roof blanket’ under metal roofs or R3.5 - R4.0 insulation with sarking for tiled
roofs (Iyer-Raniga & Wasiluk, 2007).
Sub-Task 3: Building energy performance
This gives a ‘target score’ according to the energy consumption of fixed appliances such
as cooktops, hot water systems, air conditioners, ceiling fans, lighting etc. that are to be installed
in the building
Step 1
calculate the BASIX score of “energy” of the original case study building, and analyses
the reasons why the building fails to satisfy the BASIX PASS requirement (i.e. BASIX score of
50%); Energy targets are set to ensure that a home receive net zero energy. The BASIX report
for the case study building energy performance gave a score of 21% which is below the energy
target of 50%. This means that the reduction of greenhouse gases has not been achieved hence
the building is unsustainable since heating and cooling loads have not been minimized. Some of
the reasons why the building did not pass the BASIX requirement include
 The hot water system used was not the most efficient option, instead of using electric
storage, solar energy could have been used because it is more efficient and environment
friendly. In the long run more electric energy could have saved which could have lead
into reduced greenhouse emission (Huizenga, et al., 2006).

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 Ventilation approaches adopted were not the best to help in energy saving. The kitchen
and bathroom could be naturally ventilated considering they are located on the exterior
walls of the building. This could have saved the energy used in operating the individual
fans.
 Lighting the living and dining room require energy efficient lamps since the spaces are
continuously used and require fluorescent or LED lamps. Not having the dedicated
fluorescent or LED fittings leads to more energy used (Huizenga, et al., 2006).
 Lack of a well-ventilated space for the refrigerator leads to accumulation of heat
Step 2
 In many cases designs will pass the energy targets by using typical 6-star gas
instantaneous Hot water service, reverse cycle air conditioning, LED/Fluro lighting, gas
cooktop and the installation of a clothesline (Iyer-Raniga & Wasiluk, 2007).
 If the design fails by under 5% of meeting the targets using some of the following may
help:
 Well ventilated fridge space achieves 2%
 Utilize natural lighting and ventilation as much as possible.
Step 3
Estimate the likely investment required for your developed three solutions
The incorporation of the solutions will definitely mean additional cost to the developer of up to
$300 to purchase the energy efficient fixtures.

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Step 4
Compare the three solutions you developed and discuss the advantages and disadvantages of
each solution.
The solutions proposed to comply with the BASIX requirements range from installing
appliances with good rating to help in the management of energy saving to allowing enough
space for appliances such as the fridge and making use of the natural light and ventilation to the
maximum. This combination of outdoor environment to quality indoor appliances can greatly
improve the BASIX energy requirements.
6 star appliances
Advantages
 Have a reduced energy consumption per minute
Disadvantages
 They are very expensive, this eventually increase the cost of the building
Well ventilated fridge space
Advantages
 Improve the quality of air in the kitchen
Disadvantage
 Require more space
Natural lighting and ventilation

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Advantages
 Eco friendly to the indoor air quality
Disadvantages
 More fenestration to achieve outdoor air quality and light means that there will be more
window, doors and skylights which will need glazing. Hence more spending to achieve
this design measures
Discussion
Building Sustainability Index (BASIX) is responsible to ensure that homes built in NSW are
more considerate when it comes to water and energy efficiency strategies employed in the
designs. The main aim is to reduce the amount of greenhouse gas emission in to the atmosphere
and water conservation targets as seen in the case study building. Therefore, before any
construction is done, it is important to submit the BASIX certificate of the development in order
to help secure our environment for the future.
Recommendations
Considering the analysis done, there has been tremendous failure to ensure that the design
meet the energy, water and thermal performance because of poor design decisions. It is important
for all house to comply with the BASIX requirement by having components such as the
rainwater tanks that will greatly help in rain harvesting with an average size of 4000 liters. The
majority of the water will be supplied to the laundry and toilet while the rest can be used for
irrigating the gardens.

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References
Huizenga, C., Zhang, H., Mattelaer, P., Yu, T., Arens, E.A. and Lyons, P., 2006. Window
performance for human thermal comfort.
Iyer-Raniga, U. and Wasiluk, K., 2007. Sustainability rating tools-a snapshot study. Environment
Design Guide, pp.1-14.
Appendix

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Sustainable features recommended by BASIX