The Clarke House - Sydney

This great renovation shows how a well-planned addition has improved year round thermal comfort,
reduced energy and resource consumption and lowered waste production within a tight budget.

Building Type:	Addition / renovation to existing weatherboard cottage
Climate:	Warm temperate Sydney Northern Beaches
Lifestyle modification:	Very Good
Rainwater harvesting:	Excellent
Waste reduction:	Good
Greenhouse gas reductions:	Excellent

The house, built in 1962, required extra space for an office. Because the home is occupied all day
most days, it had to be treated as a full time living area and thus had to be on the north side. The
remainder of the house was basically untouched as it had been optimised over preceding years.
The major constraint was budget - maximum benefit had to be gained for minimum expenditure.

Much use has been made of found or secondhand materials and this entire project cost less
than $70,000. The site is located on a gently rising escarpment above the northern beaches of
Sydney. The climate is mild to warm temperate. Because the site is on the north side of a spur and
within 2km of the ocean, the micro-climate is milder than the Sydney average. It is well protected
from cold southerly winds, suffers no frosts and receives cooling summer sea breezes.
The house has undergone many changes since the owners purchased the property in 1981. It has
been a test bed for many ideas and has been the subject of several on-going projects. With the
main living areas on the north side, winter sun is the primary source of heating, with summer
cooling provided free of charge by the sea breeze from the north east. Windows and doors are
placed to favour this winter sun/summer breeze orientation.

The original house had a hardwood frame with cypress pine weatherboards and plaster linings.
This has been repeated in all subsequent extensions, but with sustainable plantation timbers used
in the frame. The house is of low mass construction, which is acceptable in its climatic situation where
winters are relatively mild. The lowest night temperature is around 6°C and the lowest day
temperature rarely less than 12°C and usually 16-20°C. Insulation has been gradually added to old
walls and all new walls have had 2 layers of reflective insulation and/or bulk insulation added.
The average wall insulation value is R1.5. Ceilings have a minimum of R2.5 in the form of reflective
insulation and bulk fiberglass. Floors are enclosed by perimeter brick foundation walls, thus
providing some control of air flow to the sub-floor. The house is fitted with sliding doors and windows
to all north openings. These can be opened and locked in place to varying degrees. All windows and
doors have draught seals. There is no artificial cooling system in the house. Skylights have been
provided to internal bathrooms. These have operable venting built in. The dining room on the south
side has a Velux skylight at its southern end to increase natural lighting. There are two clerestory
windows, both of which are double glazed with a 100mm sealed air space between the glass.

Because hot air accumulates near the ceiling, creating a large temperature difference across
the window, some heat leakage to outside occurs through the glazing. Grid interactive solar power
provides a total of 1.76kw peak power in three arrays. Two are built into the roof - Building Integrated
Photo Voltaic (BIPV) - and the other is mounted to the front of it in a tilting frame, allowing for
seasonal adjustments. This array is oriented to true north, whereas the two BIPVs are oriented
with the house to 22 Degrees east of north. The PVs produce 110v DC, which is changed to 240v AC
by an inverter mounted in the office. This is near the panels with easy access for monitoring. It
records the instantaneous output in amps and volts, the total productive hours, total produced for
the day, running totals and the last 31 days' history. The inverter has a cooling fan for periods of
high load and it is mounted in a ventilated cupboard to reduce background noise in the office.

Energy Australia has a straightforward buy back arrangement using a 'reversing' meter to measure
the amounts imported and exported. The meter is electronic and records the amounts separately. The
billing from EA is easy to read and has always correlated with the owner's readings. A hybrid hot
water system, comprised of an unboosted 300 litre Edwards Stainless solar heater and a high
efficiency 130 litre Rheem Stellar gas storage heater, were installed.

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For Professional Advice, Check the website below:
Building Designers Association Australia www.bdaa.com.au/