Technical reports: Energy efficiency upgrade potential of existing Victorian houses and retrofit trials

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Energy Efficiency Upgrade Potential of Existing Victorian Houses

This report provides a detailed analysis of the potential to upgrade the energy efficiency of existing Victorian houses. It is based on a study of 60 existing (pre-2005) houses, and looks at the practical building shell, lighting and appliance upgrades that could be undertaken at the houses, the cost of the upgrades, and the likely energy, greenhouse gas and energy bill savings that could be achieved. It provides insights into the cost effectiveness of 21 different energy efficiency upgrades, the average savings and paybacks, and the diversity of outcomes which can be achieved across the houses.

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Technical Energy Efficiency Upgrade Potential of Existing Victorian Houses
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Technical Energy Efficiency Upgrade Potential of Existing Victorian Houses Word version

Refrigerator Retrofit TrialRefrigerator retrofit trial report cover

Refrigerators are found in the vast majority of houses and are one of the main electricity using appliances. Due to the minimum efficiency standards first introduced for refrigerators in 1999, and made more stringent in 2005, refrigerators that are more than 17 years old use a lot more energy than the new refrigerators sold today. This report looks at the impact of replacing old refrigerators with a new one at a total of 21 houses. At 7 of the houses the existing refrigerator was replaced with a high efficiency model, and at the other 14 houses the householders chose the replacement refrigerator. In both cases significant energy savings were achieved.

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Refrigerator Retrofit Trial
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Refrigerator Retrofit Trial Word version

Window Film Secondary Glazing Retrofit

Windows can be a significant source of heat losses from houses during winter, reducing comfort and increasing heating costs. While these heat losses can be significantly reduced by replacing single-glazed windows with double-glazing, or installing an extra pane of glass (secondary glazing), this is quite an expensive option. This report looks at the use of special heat shrink films applied to the frames of existing windows to create a double glazing effect. The retrofits were undertaken to windows in the main living areas of 8 houses. Thermal imaging was used to assess the impact of the window film on winter heat losses, and the houses were monitored to assess the impacts of the retrofits, including the cost, householder perceptions of thermal comfort, and the energy and energy bill savings.

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Window Film Secondary Glazing Retrofit Trial
Document | DOC | 24575KB
Window Film Secondary Glazing Retrofit Trial Word version

Swimming Pool Pump Retrofit Trial

While only 8% of Victorian households have a swimming pool, where they have one the main filtration pump uses a lot of energy, typically around 1,850 kWh per year at a cost of $290 to $480. In this trial old single-speed pool pumps at eight houses were replaced with new high efficiency three-speed pumps to assess the impacts. Average energy savings of 50% were achieved, giving a payback of 2 years on the additional cost of the high efficiency pump compared to a standard pump. As expected the highest savings were achieved at those houses that could operate their new pumps mainly on the lowest speed settings.

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Swimming Pool Pump Retrofit Trial
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Swimming Pool Pump Retrofit Trial Word version

Gas Water Heater Retrofit Trial

Gas storage water heaters are currently used in around 932,000 Victorian homes. In this trial old gas storage water heaters at six houses were replaced with high efficiency gas systems – five with a 5.1-Star gas storage water heater and one with a 6.1-Star gas instantaneous water heater. Average energy savings of 18.8% were achieved across the six houses for an average payback of 10.3 years. The results of the trial suggest that average household hot water use in Victoria is around 101 litres per day, substantially lower that the 200 litres per day used as the basis of the Gas Energy Rating label.

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Gas Water Heater Retrofit Trial
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Gas Water Heater Retrofit Trial Word version

Clothes Dryer Retrofit Trial

Currently around 1.2 million Victorian households have an electric clothes dryer. In this trial old conventional electric clothes dryers at four houses were replaced with 8-Star heat pump clothes dryers which generate heat using a ‘heat pump cycle’ rather than an electric element. The trial found that this replacement was currently cost effective for households with high dryer usage. Average energy savings of 69% were achieved across the four houses, giving a 9 year payback if the replacement was undertaken at the end of the existing clothes dryer’s life. As energy prices are likely to rise and the cost of heat pump dryers come down, this upgrade will become cost effective for more households in future.

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Clothes Dryer Retrofit Trial
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Clothes Dryer Retrofit Trial Word version

Draught Sealing Retrofit Trial

This report, based on a study of 16 houses, shows that comprehensive draught sealing is an effective strategy to reduce heating energy consumption in Victorian houses. “Blower door” tests were used to measure the initial air leakage rate of the houses, and to measure the impact of a range of different draught sealing measures as they were progressively applied to the houses. This allowed the effectiveness of different measures to be compared. The houses were monitored to assess the qualitative and quantitative impacts of the draught sealing retrofits, including the cost, householder perceptions of thermal comfort, energy and energy bill savings.

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Draught Sealing Retrofit Trial
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Draught Sealing Retrofit Trial Word version

Halogen Downlight Retrofit Trial

This report, based on a study of 16 houses, shows that replacing existing 12 volt halogen downlight lamps with low energy downlight lamps can significantly reduce lighting energy consumption. Halogen downlights in the living areas of the houses were replaced with low energy lamps – compact fluorescent lamps (CFLs) were used at four houses and LEDs were used at the other houses – and both the operation of the lighting and its energy consumption was monitored to assess the impacts of the retrofits. The impact on light levels and householder satisfaction with their lighting was also assessed. The study identified a range of practical issues that need to be taken into consideration when replacing 12 volt halogen downlight lamps with low energy lamps.

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Halogen Downlight Retrofit Trial
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Halogen Downlight Retrofit Trial Word version

Cavity Wall Insulation Retrofit Trial

Most Victorian houses built prior to 1991 do not have insulation in their external walls, and insulating these walls provides a major opportunity for saving energy and improving thermal comfort across Victoria’s housing stock. This report, based on a study of 15 houses, looks at the impact that installing pump in cavity-wall insulation had on the thermal comfort of the houses during winter and on their heating energy consumption. The houses were monitored to assess the qualitative and quantitative impacts of the cavity wall insulation retrofits, including the cost, internal temperatures, householder perceptions of thermal comfort, and the energy and energy bill savings.

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Cavity Wall Insulation Retrofit Trial
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Cavity Wall Insulation Retrofit Trial Word version

Gas Heating Ductwork Retrofit Trial

Gas ducted heating is currently the main form of heating used in Victorian homes. Old heating duct is often poorly insulated, may have developed holes and tears, and ductwork joins may have become loose, resulting in significant energy losses. As the ductwork is located under the floor or in the ceiling, this is a hidden problem. This report, based on a study of 8 houses, looks at the impact of replacing old ductwork with new high efficiency ductwork. Thermal imaging was used to assess the heat losses from the ductwork before and after retrofit, and houses were monitored to assess the qualitative and quantitative impacts of the retrofits, including the cost, householder perceptions of thermal comfort, and the energy and energy bill savings.

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Gas Heating Ductwork Retrofit Trial
Document | DOC | 51798KB
Gas Heating Ductwork Retrofit Trial Word version