General Information
Architect - Nigel Legge, Builder - Otto Berry
Size - 148m2, House Construction Cost - $350,000
Passive Solar Design Approach
This house is oriented to catch north-east sun and south-east views. The elevated site location was a result of planning controls which restricted the location of the house. Views from the house benefit from the raised location. The budget did not allow for a suspended slab for thermal mass. The exposed under-floor area also required good under-floor insulation to minimize heat loss. Overheating of living areas in summer is controlled by use of the casement windows for cross ventilation. An O'Erre exhaust fan with electrically operated shutters has been used in the bathroom. Raven door seals to external doors.
Construction
Floor - Hybrid timber framing and timber flooring & R5 insulation and cement sheet under.
Walls - 90mm pine stud walls at 600mm centers with R2.5 high density insulation and Bradford 'Enviroseal' breather membrane.
Ceiling - R5 insulation between joists with R1.5 Anticon blanket over roof battens.
Windows - Cedar double glazed window frames with low E film and argon in air gap. Truth
winders and catches top and bottom to casement windows. All doors and windows have
rubber seals.
First Rate Audit
A First Rate fabric energy audit rated the house at 6.6 stars.
Alternative options to improve energy efficiency looked at were;
- concrete floor slab to the kitchen/dining/lounge (+0.6 stars and ruled out on cost) and
- 75mm light weight autoclaved concrete floor with tiles over (+0.2 stars).
The total electricity bill for the April to June quarter including fixed charges, was $248, with
the 'hydro-heat' component for space heating and hot water being just $48.
Active Solar System
Hot water is provided by a Siddons 327 litre heat pump hot water tank with stainless steel
internal lining and an external condenser. This system has no element in tank so no timer is
required to ensure the element does not come on early. The HWC is located inside the
house to ensure minimum heat loss and is located next to a drying cupboard. A temperature
control mixer, at the shower with a simple on-off tap, saves wasting the water normally
required to 'run it to the right temperature'.
A Grid connected Photovoltaics System of 12 photovoltaic panels (approx 2 kW) on
the roof, and a 4.5 kW inverter providing capacity for another 15 panels.
In ground power supply to the house including three phase power to the carport which will allow full charging of a 'Nissan Leaf' electric car within 45 minutes (versus 8 hours for single phase supply).
Auxiliary Heating and Cooling
The house has an freestanding convection/radiation wood heater and a ceiling sweep fan
in the lounge with a 'back-up' floor mounted a/c unit. A 2 kW wall panel in the hall, and
under tile floor heating in the bathroom, meet remaining requirements.
Lighting
Pendant lights or suspended on surface spot lights all with compact fluorescent warm white
bulbs generally. No recessed ceiling lights into ceiling space to break the insulation layer.
Water
The house has mains water supply and a 10,000 litre water tank with closable plugs in the
downpipes for fire fighting.
(September 2011) (
