Sustainable Construction & Post-war Melbourne
This report has been compiled in order to assess the current sustainable qualities of 23 Temby Street in Watsonia, Victoria. Sitting 20km North-East of Melbourne this 578sqm allotment comfortably houses a 138sqm north-facing dwelling. An evaluation of pre-existing energy efficient and passive design features of the residence was conducted and was referenced in order to make sufficient recommendations to enhance the inherent usefulness of the dwelling. Sustainable retrofitting technologies have been explored and leveraged in order to formulate a proposal.
Watsonia reaches a maximum of 43 in the summer, with a minimum of -3 in winter, with average temperature ranging from 5-27 yearly (Bureau of Meteorology 2014). Currently the residence relies heavily on electrical or gas heating and cooling, however, conditioned air is lost and leaked due to poor insulation, draughts under doors and poorly covered windows. Whilst this residence may be labeled sustainable for the 1960’s due to a lower embodied energy in construction phase than today’s standards, it consumes large amounts of in-use operational energy to combat design flaws.
Owners of the dwelling were consulted to gather feedback on their priorities for the retrofit to ensure a holistic approach towards the balance of environmental outcomes, energy efficiency, thermal comfort properties and costing of installation and labouring of modifications. Resulted recommendations included a Do-It-Yourself draught sealing of the residence using locally bought hardware add-ons, insulating the ceiling and walls to increase thermal comfort as well as investing in floor-length lined drapes for all exposed windows in replacement of venetian blinds. Whilst together these measures resulted in an immediate outlay of costs, an approximate return on investment has been calculated to assure long-term savings and an increase of market value to the property.
Introduction
Currently, residential housing accounts for approximately one fifth of Australia’s greenhouse gas emissions and over 17.5% of our total energy use (State Government of Victoria 2013). Of this, more than three quarters remains acquired from fossil fuels, assisting in the pollution of our atmosphere and contributing significantly to global climate change (Cunningham & Cunningham 2010, p16). The fears of a warming planet bring to light topics of food security, uninhabitable land, agricultural burdens and health threats. It is imperative that individuals in life and living try and reduce their carbon footprint. A simple and effective way to make a difference is through the retrofit of housing to reduce energy consumption and water usage. Post WWII mass production became increasing favourable, which by design, highlights the end result and marginalises the process or consequences of said production. It is now a common thought that mechanically driven results are not a suitable substitute for good design. This has drastically improved the passive design properties of newly built homes, however older generational dwellings continue to present issues of energy inefficiency. Luckily, there is a plethora of retrofitting measures that can be taken to improve the thermal properties, comfort and sustainability of older homes.
Discussion
Evaluation of House
Built in the 1960’s post war period the front facing cream brick veneer dwelling in question served as a cheap and easy production option for the mass economic class. This contemporary 3-bedroom single storey residence on a 578sqm allotment boasts for its era a double garage to the rear of the block, wide front yard and timber floor coverings. Refurbished in the last ten years additions have been made to include gas cooking/heating and timber blinds, with the entire interior repainted/redecorated. Original features include working brick chimney, wire mesh doors, single glazed top hung awning windows with wooden framing, interior plasterboard walls and a medium pitched terracotta tiled roof, with low brick fencing and a narrow parameter garden to enclose the block. The north facing orientation of the house, external retractable heavy canvas awnings and surrounding eaves assign themselves to current environmental features that aid in the reduction of energy consumption. Whilst the concrete foundation lends to an increase in the thermal mass capacity of the dwelling, the deciduous tree blocks summer sun from the main indoor living space and energy saver light bulbs are installed to save energy and reduce greenhouse gas emissions, additional home energy retrofitting measures are to be analysed to increase the passive solar design potentiality.
Retrofitting Ideas & Measures
Heating/Cooling
Latest statistics suggest that heating and cooling are together responsible for using over 40% of household energy in the average Victorian home (Milne et al. 2013). Australian Bureau of Statistics (2012) states that 34% of Victorian’s use air conditioning for cooling less that one month per year compared to 29%, which use main heating for over six months annually. It is clear from this data alone that there is inherent need for passive heating solutions. Whilst thermal comfort is subjective, passive design elements can be utilised to capture solar gain, increase the natural resilience of the dwelling to exterior climate, reduce the need for electrical or gas heating, and as a result cut energy bills. It is also estimated by Milne et al. (2013) that for every degree of extra heating or cooling from mechanical devices, energy bills can increase by up to 10%.
A north facing design with surrounding eaves will enable rewards from drawing in low winter sun heat energy, assisting also with blocking high summer sun. However, a lot of passive heating or cooling can be allied with behavioural decisions. Using doors to create air locks in winter or drawing blinds or curtains prevents the escape of warmer air, while opening windows and external doors during summer attains cross ventilation and assists the dwelling to naturally cool. This disadvantage of such a behavioural solution is that it relies on the attention and care of an individual or tenant.
Windows & Doors
Up to half of all heat loss from a dwelling can be due to air leakages across the building fabric (Morgan 2006, p. 4). It is vital to create an airtight building in order to resist unwanted air infiltration without, of course, compromising the ability to ventilate the dwelling. Air leakage can decrease the thermal effectiveness of a property by up to 70%, generating a huge cost to owners (Baker 2008, p. 17). Existing older properties can minimise the aforementioned by ensuring airtightness by draught sealing and weather striping all windows and below and around all doors. Upfront capital costs are low and are drastically offset by long-term savings on energy bills, sometimes as high as 40% (Morgan 2006, p. 7).
Whilst it is preferable in Victoria for windows to be located on the north of the residence to capture the lower winter sun, existing dwellings with east or west facing windows, capturing the undesirable early or late summer sun are able to make retrofitting measures in order to counterbalance the affects if necessary. Internal window coverings and an increase in tinting or glazing can reduce winter heat loss by approximately 40% (Sustainable Energy Authority Victoria 2014, p. 20). For east or west facing windows lined or double thickness curtains, draped to the bottom of the window frame, can reduce this even further.
In addition, external shading can block up to 80% of summer heat with options such as external awnings, eaves, pergolas, verandas, shade sails, or the planting of deciduous trees (Sustainable Energy Authority Victoria 2014, p. 20).
External Shading
Acting essentially as a glass house, windows create a path of least resistance for heat loss or gain with energy inefficiency properties sometimes senselessly overlooked in favour of aesthetics. Eaves that extend one metre on the north wall and external awnings can block out up to 70% of heat gain during summer individually (Sustainable Energy Authority Victoria 2014, p. 27). Eaves are an extremely practical way of shading windows and external walls from the high angle summer sun. This feature is of even further importance to brick homes, which act essentially like a heat sink during summer months and need to detract direct sunlight. In addition to boasting passive energy properties, eaves also aid in waterproofing and can slow down the ageing process of a property.
Broad leaf deciduous trees correctly placed in front of exposed windows are an effective way of letting light in during winter months with the shedding of foliage, blocking excess solar light during summer months due to absorption and photosynthetic reactions. While this option might incur ongoing maintenance it will also value add to the property aesthetically.
Water Tanks
Melbourne, and specifically Watsonia with a yearly rainfall of 582mm, exhibits seasonal rain dominant weather and as a result is fit for capturing rainwater runoff from roofs (Melbourne Water 2014). Installation of a 2000L water tank can save up to 50,000L of water per annum and help to reduce water consumption for clothes washing, toilets and use in the garden (Environment Victoria 2014). Whilst up front costs are steeper than other retrofitting measures, costing upwards of $2,500 including installation costs, the Victorian and Federal governments offer rebates beginning at $900 (Department of Environment and Primary Industries 2014). Ongoing maintenance is also required to ensure rooftop catchment areas are kept clean and free from debris or sludge. Whilst this proactive approach will also ensure the upkeep of your property, water tanks are also known to reduce the impact of storm water on drainage infrastructure (Environment & Heritage 2014) This measure can direct the property towards self-sufficiency, eradicating water bills long-term.
Insulation
Whilst regulations for newly built homes in Australia stipulate the need for insulation, a large proportion of older homes remain un-insulated. In addition to this, older generations of homes present minimal insulation with low thermal resistance (R-values.) Uninsulated or poorly insulated ceilings and walls can account for dramatic heat loss, decreasing the thermal comfort of occupants and the energy efficiency of the dwelling. An improvement in thermal performance due to insulation can amount to $478 of savings on yearly energy bills and over 1.48 tonnes of greenhouse gas emissions (Energy Efficient Strategies Pty Ltd 2011). Creating a barrier for heat energy, a fully insulated home reduces the need for space conditioning and as a by-product can improve health outcomes for tenants. Insulation for Melbourne dwellings, requiring a ceiling rating of R3.5 or higher, can cost approximately $1750 for glasswool or polyester batts and double-sided foil insulation (to help keep the summer heat out) (Environment Victoria 2014). Whilst upfront costs are high, with payback periods commonly of 3 years (assuming 40% Do-It-Yourself), the return on investment neutralises initial capital by increasing the energy star rating of the property, and in consecutively the worth. (Energy Efficient Strategies Pty Ltd 2011, p. 25).
Lighting
Lighting represents approximately 6% of electricity usage in the Australia household. (Living Greener 2014). Effective and thoughtful lighting design aids to direct natural daylight sun where desired, shading and glazing unwanted light and heat during unfavourable conditions, decreasing overall energy usage. Do-It-Yourself cheap and easy measures can be taken, for example, painting the interior walls a lightly coloured cream or white to reflect incoming light and reduce the need for artificial lighting. Choosing appropriate light fittings can also radically affect energy bills with LEDs proving to almost halve the energy consumption and double the expectant lifetime 20 times over of halogen lights (Barrett, S 2012). Although LEDs can cost upwards of ten times the price of Halogens, rebates can be claimed via the Victorian Energy Efficiency Target (VEET) scheme.
Solar & PV Cells
Water heating is known to be the second largest energy consuming appliance accounting for 23% of residential energy use, with solar heating or solar hot water presenting as recommended sustainable retrofitting measures (Energy and Resources 2010). Energy and Resources (2010) illustrates that currently electrical heating is costing the average Victorian household yearly running costs of up to $732. Whilst installation for a solar hot water system may typically cost $2300 more than electric heaters, Commonwealth rebates of $1600 likens the gap fee to replacement costs of an electric water system.
Water Conservation Measures
The most effective water conservation measures include the use of a greywater system or low-flush toilets. However, both measures are relatively expensive upfront with the need of experienced tradespersons. Much similar to rebate schemes set up by the federal government to enhance energy efficiency through light bulb upgrades, the Showerhead Exchange Program allows Victorian households to swap two old showerheads per house for free 3-star rated water-efficient showerheads. This measure not only helps to reduce over one tonne of greenhouse gas emissions but can also save over 50,000L of water annually (Environment Victoria 2014).
Unfortunately, a lot of water-conservation-techniques are reliant heavily on behavioural decisions and attitudes towards sustainability issues. Easy, cost-free and effective ways to save water around the house include shorter, 3min showers, turning running taps off when not in use and eradicating the use of water dependent plants in gardening. Approximately 50L of water can be saved by only washing dishes when the dishwasher load is full (Sarac, K 2013). Correcting behavioural mannerisms, whilst resting on the performance of individuals, is a cost-free measure to reduce residential carbon outputs.
Energy Sources
Currently 87% of Australia’s energy supply is generated by fossil fuels, increasing the Carbon Dioxide levels in the atmosphere and in turn creating a self-perpetuating feedback cycle triggering devastating global environmental impacts (Cunningham & Cunningham 2010, p16). Cunningham et al. (2010, p. 447) describe renewable or sustainable energy as energy that can be used from a source at a rate that enables usage to continue indefinitely. Alternative energies include solar energy, hydropower, wind power, wave power and geothermal power. Presently the only efficient commercially available renewable option for city-based residential dwellings is solar power and the use of PV cells. (Cunningham & Cunningham 2010, p453). A simpler and cheaper option to solar, creating an immediate impact on a residential carbon footprint of a dwelling, is to purchase a percentage of your energy from GreenPower® through your electricity provider, investing in the renewable energy industry and potentially offsetting the electricity the dwelling expends. GreenPower®, a Government accredited renewable energy source, for 10-25% of the total of a households electricity bill, can potentially cost just $1 per week (GreenPower 2014). GreenPower (2014) suggests that purchasing 100% of the household energy bill from GreenPower®, the average Australian household would be roughly outlaying just $1.50 per day for 15-18kWh usage.
Chosen Retrofitting Measures
The owners of 23 Temby Street, Watsonia have communicated that near-future retrofitting measures should cover the criteria of a) are reasonably priced, maximizing the potential of return on investment and b) limit labour intensiveness. Considering the owners have only occupied the dwelling for the last 6 months it is understandable that they wish to avoid further dramatic outlays of costs so soon after the purchase of the house.
Unfortunately, the dwelling at 23 Temby Street is part of the Australian statistic of uninsulated homes. Whilst committing to correctly insulating the ceilings and walls might see outlays in costs of $1750 the occupants are expected to see savings in the first year of between $300-$475 on energy bills (Energy Efficient Strategies Pty Ltd 2011). Payback period’s range can range from between 3-8years with 6-7 year payback attributing a 5% discount. (Energy Efficient Strategies Pty Ltd 2011, p. 9) Energy Efficient Strategies Pty Ltd (2011, p. 28) suggests that the decision to retrofit ceiling and wall insulation could add 2 stars to the energy rating to this dwelling and could see a 10% return on investment. Sitting just slightly higher than the median house prices of Victoria (The Real Estate Industry of Victoria 2014), each energy star rating could potentially add over $11,000 to the sale price. (Energy Efficient Strategies Pty Ltd 2011, p. 28) With energy prices continuing to increase it can be estimated that the market might even respond more favourably to energy efficiency than this proposed figure. It is also important to acknowledge that commonly the outcome is more than a sum of its parts, with insulation contributing more than thermal performance, combatting noise pollution from the neighbouring Greensborough Highway.
Currently the property exhibits poor airtightness with doors and windows far from draught sealed. In order to create an airtight residence the occupants must commit to a Do-It-Yourself project, fitting weather strips, draught seals and stoppers to all doors and windows. Permanent weather strips and door sweep fixtures are recommended to seal gaps beneath and around doors and help to meet stiles of double doors in the living areas. To combat air leaking from beneath doors, door sweeps can be purchased from a local hardware shop for $12-$15 per door, totaling a maximum $60 for all interior bedroom and living room fix-ups (Bunnings Warehouse 2014). For uninhabitable rooms such as the kitchen, laundry and bathroom Do-It-Yourself door snakes (lightweight, removable stuffed strips of fabric) can be used, costing less than $5 each (Environment Victoria 2014). With an outlay cost of less than $300 to draught seal the entire house (including approximately $100-$150 to draught seal all windows) with labour Do-It-Yourself taking less than one day for installation, the immediate benefits of a reduction in energy bills (up to 25% off) and increase in thermal comfort far outweigh any out-of-pocket expenses (Living Greener 2014).
There is a potentiality of up to 40% of thermal heat escaping from the Temby residence during winter due to the poor window coverings (Environment Victoria 2014). Currently, the residence relies on interior timber venetian blinds to create thermal resistance during winter. Unfortunately, this would have little to no effect on the thermal properties of windows during winter. Fortunately however, the installation of heavy, lined drapes inside a pelmet box, reducing heat loss by up to 47%, is a cheap option in order to combat this problem (Sustainable Energy Authority Victoria 2014, p. 20). Relying on Do-It-Yourself labour work to install pelmet boxes and hang curtains costs are estimated at $180 per window for ready to hang, lined and double thickness curtains (Environment Victoria 2014). However, if wanting to cut costs even further, curtains can be recycled from Opportunity Shops or Garage Sales. When associated costs can be afforded, Sustainable Energy Authority Victoria (2014, p. 20) indicates thermal properties can be improved again by up to an additional 17% through double-glazing of windows.
Conclusion
The ever-increasing population of developed and non-developed countries alike has fashioned an enormous amount of pressure on the limited global resource supply of fossil fuels to aid in development both commercially and residentially. To avoid the catastrophic consequences of resource depletion we must align with sustainable development models and revolutionise our way of thinking.
Since May 2011 all new homes built within Australia have had to comply with a 6-Star Energy Standard, however many residential buildings erected or renovated prior to 2005 currently have Energy Star Ratings of below 2 (Sustainable Energy Association of Australia 2011, p 6). There is enormous potential to leverage from these energy-inefficient dwellings to reduce national carbon output and in turn lessen greenhouse effects. The Federal Government and Victoria Government alike has responded by sufficiently subsidising energy efficient retrofits and allowing such dwellings to improve thermal comfort levels, provide cost savings on energy bills and increasing the overall resilience to climate change.
The three recommended retrofits for the 3-bedroom residence at 23 Temby Street, Watsonia include a Do-It-Yourself draught sealing of the residence, ceiling and wall as well and investment in floor-length lined drapes for all exposed windows in replacement of venetian blinds. Immediate costs for this retrofit would sum to just under $3000, however comfort benefits would be identified almost instantly with a saving of approximately $600 on energy bills in the first year. An improvement of 2-3 Stars on the energy rating of the property would also show a substantial return on investment of roughly $22,000 on market value of the property (Energy Efficient Strategies Pty Ltd 2011, p. 28)
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