MARRICKVILLE RESIDENCE
Anthony Nolan, Kennedy Associates Architects, 02 9557 6466
Our office has had a long track record of producing, researching, and advocating for, architecture that is both "green" and beautiful. When the opportunity came along to undertake work on my family home it presented an excellent opportunity to live by my professional advice and to share then these experiences beyond the office.
Our house is a fairly unremarkable freestanding double brick house with tile roof on a modestly sized relatively flat site, located within Marrickville in Sydney. When we purchased it we did all of the usual things, such as ripping up carpets and sanding floors, we repainted with Low VOC and no VOC paints, sealed air vents in walls to reduce drafts, purchased green power, added ceiling fans, added ceiling insulation, had gas outlets installed for space heating and started establishing a native garden. But as time went by we noticed that our electricity, water and gas use were all increasing from year to year. Some of the increases were easy to understand, for example we had kids, and added an in-ground pool, but many of the increases were less easy to identify, and this set me on a path to understand, and ultimately reduce, these impacts.
Water use was the first area that we addressed and we did this by connecting a 5000L rainwater tank to the laundry, toilet and garden taps when we added the pool. The tank is located below the front garden and is fed by all of the downpipes of the house. The tank has a mains diverter for times when it runs dry and has operated reliably for several years. We've recently upgraded the system to make it more robust by adding leaf guards, and a more sophisticated filter to the line feeding the house. Locating the tank below ground added considerable expense, risk, and materials to the installation and on balance I think an above ground tank would have been better in the end.
We also addressed water use through the purchase of a front loading washing machine, and fitting water saving devices throughout.
The swimming pool uses little additional water in the end, largely due to the installation of a roll out pool cover. The pool cover has been integrated into the design of the pool equipment shed and is easy to use, it also helps to keep leaves from the pool and improves the thermal efficiency of the pool. I can't believe that anyone builds a pool without a pool cover. The social impact of the pool is huge as we share it among freinds and family.
We also added a hot water diverter to the bathroom that flushes cold water into the rainwater system while waiting for the hot water to arrive from the heater.
Recent works to the house added a greywater diverter from the bath and shower that is connected to a subsurface irrigation system located throughout the rear yard
Health impacts that the house was having upon us became more of a concern over time as the house was relatively damp and many rooms had mould problems. Addressing the mould required improving ventilation and addressing the various sources of moisture. The un-flued gas heater was an obvious source of moisture vapour, and toxins, and we decided to replace it with a built in flued gas heater. The heater has a separate air intake flue and gas exhaust flue and it has transformed the house, the air is cleaner, the house is less drafty, and mould has all but stopped.
Further improvements to indoor air quality have been obtained by installing a vapour permeable sarking below the floor boards to separate the air in the subfloor from the air in the house, installing additional ventilation to the subfloor, and ducting the bathroom exhaust directly to the outside rather than into the roof space. Clothes are also no longer dried on a rack in front of the heater and we have installed a clothes dryer that is ducted externally.
Future work to the house will improve control over ventilation by improving weather seals to doors, adding lockable cross ventilation to each room and directly exhausting the kitchen to outside.
Electricity use was the most difficult to reduce. We needed to take what we've learnt about saving water and apply it to saving electricity, and we did it by addressing both supply and demand reduction. Electricity supply was addressed by installing the largest solar system that we could fit. This was limited by roof geometry and roof area and we ended up with a 2.25KW system that is producing about 9KWh of electricity a day averaged over the year. To maximise the effectiveness of the system we decided to retain our RECS and have maintained our green power.
To reduce electricity we did all of the obvious switching off of lights and turning off stand by power but large savings only came after we conducted extensive monitoring of electricity use across the various appliances within the house using a PowerMate. The washing machine proved to be a large user of electricity and after a lot of experiment we've now settled on the most energy efficient settings. We also changed the pool pump to a variable speed DC motor, and reduced hours of operation even lower. We've also limited the use of the electric oven, switching to gas depending on what we are cooking. We've reduced electricty use over the past months from about 15KWh per day to 9KWh per day.
Gas use has been the simplest to reduce and we've installed a gas boosted solar hot water unit for domestic supply and have replaced the gas heater to the pool with a pool solar heater. During summer we reduced gas use by about 90%, autum was about 75% and winter has been 25%. Some of the gas savings are offset by higher electricity use to run the pump for the solar pool heater, and the additional hours of operation for the pool pump.
We also made significant reductions in greenhouse emissions by fixing a gas leak by replacing all of the galvanised gas pipes with new copper pipes back to the main. This is significant as un-burn gas has a greenhouse impact about 20 times that of burnt gas.
Materials used in the renovations to the house have included radial sawn timber, plantation plywood, and reclaimed sandstone from a building demolished on site.
Design has of course been very much at the forefront of much of the thinking behind everything that we've done as we've focussed on creating a liveable family home that is beautiful to live in and is flexible enough to suit our needs going into the future. And we still let the kids ride bikes through the house...............
(August 2011) (
