Sustainable House Day, Maryland, NSW

 

‘Gaia’ Dominican Sisters   This is a 14 year old project home in one of the newer Newcastle suburbs: Maryland. Bordering the Lower Hunter National Park, suburban run-off, chemical pollution and feral weed encroachment pose a significant issue for wetland remediation. Two years ago the house was renovated to make it more environmentally sensitive and as self-sufficient as possible.   New or Retro: retrofit residential   Climate Zone: Coastal Temperate   Water Harvesting: •       Four above ground rainwater tanks. (250 litres – storage for gravity watering front garden; 2,500 litres – roof fed from garage area used for garden and extra storage; 5,000 litres storage overflow from other tanks; 5,000 litres charged water roof fed, plumbed into house used for household ). Guttering has been covered with leaf guards and the two roof-fed rainwater tanks have first-flush diverters. •       Aquareuse Grey Water Treatment (2,000 litres capacity per day) from bathrooms, laundry and kitchen discharge. Used for laundry, toilets and garden. •       While our water rates are about $140 per quarter our actual usage component is about $2 per quarter.   Special Garden Features The house is on an east facing sloping 650sq metre block. Using principles of permaculture design, the western boundary has been planted with shady native trees, which in turn protect a number of fruit trees and then garden beds. Swales and deep mulch slow down stormwater run-off. The house provides shelter for other vegetable beds. Chooks and composting are rich sources of soil nutrients.   External Walls  The house is a standard brick veneer with dark coloured roof tiles. Western windows are shaded in summer by canvas blinds. Shade cloth awnings give summer shade in the south and north. In the east the laundry provides a heat barrier for the rest of the house (provided we remember to close the laundry door). In winter the large window area in the north and west gives maximum heat gain during the day and thick curtains conserve heat and avoid the need for artificial internal heating.   Internal Walls Mostly gyprock and glass. There are limited sources of cross-ventilation. Insulation is from R2 gold glass batts.   Roof Dark tiles are a negative feature. There are wide eaves with air vents on the north and east to provide heat exchange with whirley birds. Pitch and orientation were ideal for solar panels but left little north-facing space for the solar hot water system which now faces east.   Floor Slab construction and siting of large north-facing window afford good thermal mass. Carpet in the back room will later be replaced with ceramic tiles to improve the floor’s heat retention capacity.   Window treatments Ajustable west-facing canvas awnings. All windows are fitted with mostly floor-length insulating curtains and pelmets. One south facing window has a mirror reflector to capture winter sun for the office. No window is directly exposed to summer sun because of the use of removable shadecloth awnings.   Electricity Generation We reduced our daily electricity use to an average 6kW hours with low energy appliances, turning off unused equipment that would normally be on stand-by and by purchasing Green Power. We have a smart electricity metre which charges by peak, shoulder and off-peak units. We have tested our appliances using a Power-Mate Lite metre to determine accurate usage. A 1.6 kW solar power system over a year has reduced our power bills by 75%.   Heating and Cooling Occasional gas heating of family room. Ducted air conditioner used when indoor temperature reaches over 33 degrees. In 2008-2009 both appliances only were used about three days each. Mostly passive solar heating and shading keeps the temperature between 18 to 24 degrees all year.   Water Heating Apricus Evacuated Tube Solar Hot Water system installed. Electric back up.