Milan 29 by Arden Homes
Milan 29 with Harper façade. This display by Arden Homes demonstrates that its possible for a modern home to easily achieve a 7-star rating without compromising on style. These builders understand the importance of orientation, insulation and glazing upgrades required to achieve 7 stars and the savings associated with the choice to include all electric appliances.
Feature home snapshot
Builder: Arden Homes
Location: 26 Origin Drive, Sunbury Victoria – NatHERS Climate Zone 60
Design: Milan with Harper façade
Description: Single storey, 4 bedrooms 2.5 bathrooms
Size: Total area: 264.19m²
House area: 220.68m²
Garage: 37.54m²
Porch: 5.97m²
NatHERS energy rating: 7 stars*
Whole-of-home assessment: All electric with solar PV and battery
*This home has been rated using FirstRate5 5.3.2b under NCC 2019.
Energy and cost savings
Using Sustainability Victoria’s Whole of Home Pilot Tool, the estimated annual energy use, emissions and energy bill amounts were calculated for this home and compared to the same home built to the current minimum requirements under the current version of the national construction code, 6-star NatHERS rating with average efficiency mixed fuel appliances without solar PV. Thanks to the 7-star NatHERS rating and the selection of all-electric appliances, solar PV and battery, the new owners of this home are expected to save 68% each year on their utility bills. Due to the addition of a solar PV system and battery storage this home has a negative energy usage and –1,72 tonnes of CO2-e emitted each year.
| 26 Origin Drive, if it were a mixed fuel 6-star home without solar PV | 26 Origin Drive (actual – 7-star all-electric home with solar PV and battery) | Savings [%] | |
|---|---|---|---|
| Annual energy use | 54,799 MJ | -6,167 MJ | 111% |
| tCO2-e emitted p.a. | 5.6 | -1.72 | 131% |
| Annual energy bill | $2,417 | $769 | 68% |
Table 1: Predicted annual energy use, emissions and costs, including supply charge for 26 Origin Drive under a business as usual and as built scenario.
Annual consumption by end use area
The annual energy consumption of the home has been calculated and is demonstrated in the graph. When modelled as an all-electric home, 26 Origin Drive has most of its energy consumption used by plug-in appliances, closely followed by the heating system. When modelled as a mixed fuel home (using gas for heating, hot water and cooking) most of the energy consumption in the home is assigned to the heating and plug in appliances, followed by the hot water systems.
Milan 29 design living room. Home features
| Feature | 26 Origin Drive, if it were a mixed fuel 6-star home design in the same climate zone with mixed fuel appliances | 26 Origin Drive 7-star (as-built) |
|---|---|---|
| NatHERS rating | 6 stars | 7.1 stars |
| Design orientation | Northwest facing at the rear of the site | Northwest facing at the rear of the site |
| Insulation - ceiling | R3.5 batts and R1.3 anticon roofing blanket to ceiling (garage ceiling has anticon roof blanket) | R7 batts and R1.3 anticon roofing blanket to ceiling including garage ceiling |
| Insulation - external walls | R2.0 to external walls | R2.7 to external walls |
| Insulation - internal walls | No insulation for internal walls | R2.7 to all internal wet area walls (all interior walls insulated for acoustic benefit) |
| Windows | Double glazed to kitchen/living/dining, theatre, hallway (4/10 argon fill/4) | Double glazed (4/10 argon fill/4 to all windows) |
| Hot water | Solar hot water system - gas boosted | Heat pump hot water |
| Rooftop Solar PV | N/A | 6 kW Solar PV system and 14kW of battery storage |
| Heating and cooling | Gas ducted heating, no cooling | Ducted reverse cycle heating/ cooling system |
| Lighting | Maximum 5 W/m2 | 2 W/m2; energy-efficient LED lighting |
Milan Home floorplan (Copyright: Arden Homes). Home design
The Milan design by Arden homes features a compact and efficient floorplan. The living area opens out to a generous sun court, which doubles as an additional outdoor lounge area. This single storey home comes in 26 and 29 squares and is from the Aspire range.
The Milan design features:
- 4 bedrooms, with walk-in robes
- a main bedroom with a large ensuite and walk-in robe
- additional home theatre
- 2 bathrooms
- an all-electric kitchen and walk-in pantry
Some of the key decisions involved in this home achieving 26 Origin Drive’s 7-star NatHERS rating are outlined below:
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Arden Homes know how important orientation is in achieving an energy efficient design. They offer genuine design flexibility on all designs in the Aspire range. This allows each home to be tailored to suit the block orientation and maximise the amount of daylight that the home receives. The NatHERS rating of this home design could reach beyond 7 stars by simply flipping the rear to allow the lounge and dining rooms to receive more light from the north.
Some of the key decisions involved in this home achieving its 7 star NatHERS rating are outlined below:
- Locating the main living areas to the northern end of the home.
- Locating bathrooms to the west.
- A sun court which allows the northern light to enter into the home theatre and hallway.
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To achieve the current NatHERS standard of 6 stars, this home requires a mix of double glazing (4mm glass/10mm argon-filled gap/4mm glass) to the kitchen/living/dining, theatre and hallway. Single glazed clear windows were selected in all other rooms. To achieve the 7 star rating this home requires double glazing (4mm glass/10mm argon-filled gap/4mm glass) with standard aluminum frames to all rooms.
Some of the other strategies employed in this home to get the most out of its glazing are:
- locating main living space windows to the north-east aspect
- reducing the bedroom windows sizes facing west
- including a sun court which allows the home to advantage of the northern sun and bring it into the centre of the home.
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Insulation helps to reduce the transfer of heat through walls roofs and floors. To go from 6 to 7 stars the insulation upgrades in this home include:
- upgrading ceiling insulation from R3.5 to R7.0 batts to ceiling including garage ceiling.
- the use of anticon roof blanket provides additional insulation to the ceiling and the garage.
- upgrading external wall insulation from R2.0 to R2.7 batts
- upgrading insulation between the home and the garage and adding or upgrading insulation in internal walls around wet areas. Including R2.0 batts.
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The use of all-electric appliances combined with solar PV and battery storage mean the residents of this family home will be saving 68% or approximately $1,648 annually on their energy bills, compared to if they built this home to the current minimum 6-star standard. This all-electric home features:
- all-electric cooking appliances including induction cooktop
- energy-saving solar panels
- ducted reverse-cycle heating and cooling
- integrated heat pump hot water service
- double glazing to windows
- LED downlights
- three phase power.
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The design of the roofline can have a huge impact on the size and efficiency rooftop solar so it's important to remember that:
- different facades will work better in different orientations
- designs with simple rooflines can maximise space for solar PV
- north facing solar is best but a combination of east and west works well too.
Arden Electrified means that all new homes are set up to be ready to electric vehicles, now or in the near future. To allow for electric vehicle charging all homes have:
- 32 amp cable from the switchboard to behind the plaster in the garage at the future charger location
- 2 extra blank slots in the switchboard
- run conduits from the switchboard to charger location and solar invertor to allow for future data cables and home battery integration
- consider adding an extra 2kW to the solar PV to allow for car charging (50km/day average).
Material colour selection
Milan home design with different façade options showing a range of colour choices. It's worth considering the impact of colour choices early in the design process. Rating improvements can often be achieved by lightening external roof and wall colours.
Home construction
To meet the requirements of Sustainability Victoria’s 7 Star Homes Program the builders were required to pay extra attention to their construction practices to produce good-quality outcomes. The construction process for this home involved some additional steps ensuring the quality of the final build:
- Additional care has been taken when installing insulation, ensuring coverage is continuous and free from gaps. This includes around windows and at external corners and wall junctions which are commonly missed.
- A plaster airtightness strategy has been employed, including caulking of plaster to the concrete slab, caulking service penetrations and caulking and sealing around cavity slider doors.
- All exhaust fans and the kitchen rangehood are fitted with in-line dampers and are vented externally. This prevents draughts and reduces issues with condensation associated with extraction fans venting into the roof cavity. Quality exhaust fans ensure a healthy indoor environment.
Milan 29 kitchen showing the induction cooktop. As-built verification
Sustainability Victoria engaged an independent as-built verification assessor to ensure that the home was built to meet its intended energy efficiency targets. The verification check included a blower door test to measure air leakage, a thermography test to check insulation coverage and visual inspections of glazing, ceiling insulation, extraction fan vents and appliances.
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The home was blower-door tested to determine the air leakage rate. The home passed the blower door test with an air-permeability of 4.32 m3/h/m2 @ 50Pa, which is good result and well below the requirements of the National Construction Code. This result was achieved by using the plasterboard as an air-tightness layer.
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This test uses a thermal imaging camera that can ‘see’ heat, enabling the assessor to inspect the installation of insulation, by looking for hot spots and cold spots in the ceilings and walls. The inspection is passed if no more than 5% of insulation is missing in the walls, floors and ceilings.
When the home was first tested the thermal images showed some missing ceiling insulation in areas where the ductwork had been installed. Using this knowledge the builders were able to quickly rectify this error and upon re-testing, the home passed impressively with no missing insulation in the ceiling and the walls.
Summary
Arden Home’s displays in the Villawood Redstone Estate in Sunbury demonstrate how designing and building 7-star homes can be easy and efficient. The Milan 29 display easily rates at 7 stars by upgrading to double glazed standard aluminium framed glazing along with insulation upgrades. Arden Home’s design flexibility means that this or any other Aspire floor plan can be flipped to be optimised for the ideal orientation to make the home light and bright. The standard inclusion of all electric heating, hot water and cooking with solar PV and battery storage will save the future occupants of this home 68% on their annual energy bills.