Sustainable House Day, Alice Springs 1, NT

This house shows the retrofitting and upgrading for a typical ex government built housing stock typical for the area. The house shows the retrofitting and upgrading to achieve energy efficiency and solar technologies

New or Retro: This is an example of retrofitting to an existing domestic residence

Climate zone: Arid zone – hot dry summers and cold dry winters with an average of 47  cloudy days per annum

Unique Sustainable Elements featured in this home

House orientation and shading: The house is orientated within  5 degrees of east – west.
The eaves on the northern side provide shade to the walls in summer and allow the sun to strike the walls and windows in winter, providing heat gain to the house.
The veranda and trees on the eastern side provide shade to the walls and windows in summer and again allow the sun to penetrate in the early morning in winter.
The carport on western end of the house provides shade to the western wall.

External walls: The external walls of main body of the house are double brick walls which usually have a thermal resistance of approx R 0.8. The external wall cavities have been retrofitted with EPS foam (with suitable wiring changes) to improve the thermal resistance to approximately R2.5.

Internal walls: Internal walls are brick which has a high thermal mass. This property is utilised in the solar air heater which only runs during the day and the walls store the heat which is released in the evenings

Roof and ceiling: The roof is painted with white Solarcoat® paint, which reflects heat in summer, maintaining the roof sheeting within 10 degrees of ambient temperature
Sisilation/aircell membrane is installed under the roof sheeting (aircell has been installed under the roof purlins where the sisilation has deteriorated due to age)
R3.5 insulating batts are installed above the ceiling throughout the house.

Window treatments: Windows are a large source of heat loss or gain. During refurbishment, the windows were fitted with doubled glazing and close fitting blinds, reducing heat transfer by 50%.

Solar PV: A grid connected  PV system through the Solar Cities program, comprises 1980 watts of photovoltaic panels (12 x BP3165 panels), facing north and inclined at 15 degrees, coupled to a SMA SB1700 (1550 watt) grid connected inverter. The output of the PV system is 3300 kWHrs per year. Rebated system cost is $10,500 with expected payback of 10 years. Annual savings of greenhouse gas emissions is 1.98 tonnes of CO2

Solar Air Heating: A custom designed solar air heater provides heated air to the lounge room. This circulates air from the room through the solar heater during the day. It relies on the thermal mass of the internal brick walls to store the heat and release it during the evening to the room. The panels are installed at 40 degrees to optimise heat collection during winter.

Solar Water Heating: The existing Solar Hot Water Service is a mains pressure 160 litre Beasley unit.
This unit is 26 years old and proposed to be replaced with a Solarhart 300 litre dual panel SHWS.
The average household usage of hot water was 20 litres per person per day (4 people in the house = 80 litres per day before water efficiency measure wee implemented.
As this size system is recommended for a unit (2 people), It does not cope well for three months in winter, requiring the electric booster to be used. The booster is on timer in winter set to 5:30 to 6:30 am to maximise solar production during the day and ensuring hot water for morning showers. Under this arrangement the SHWS currently is reduced to about $100 per year of electricity.

Lighting: Fluorescent lighting is utilised throughout the house, predominantly compact fluorescent lamps

Solar Pool Heating: The heater consists 360 metres of black poly pipe is installed on the carport roof in 3 concentric coils to provide heating for the pool when required. This is fed from a manual changeover valve after the pool circulating pump.
Ventilation and Draughts: External Doors are fitted with draught stoppers. Wall vents have been covered to prevent loss of heated air during winter by convection up the wall cavity.
A draft stopper is fitted to the exhaust fan in the bathroom to prevent heat loss when the fan is not in use.

Garden: The front garden is an arid region style garden fed by a dripper system on timers. Trees are located to provide shading and privacy

Appliance Standby Power: Appliances such as the TV and video are fitted with switches to enable the appliance to be turned off to eliminate standby power losses
The family computer is fitted with a USB switched power board that switches off the peripherals when the computer shuts down ( programmed after 15 min of inactivity)
An in house display is fitted which displays both the solar production and house load, enably the household energy usage to be monitored