O’Connor Low-Energy Straw bale house 2025

O’Connor Low-Energy Straw bale house

Knock down rebuild.
Started with a very cold monocrete house which had an EER of zero (which was generous).
Dismantled and reused:
• Timber from below (joists and bearers) and above (trusses and rafters) – reused for stairs, bookshelves and window sitting-sill
• Canberra red bricks
• Polyester Batts for use in internal walls
• The enormously heavy cast-iron bathtub which came up a treat re-enamelled
The new house is certified as a Low energy building under the Passivhaus scheme, as it only needs 15% of the heating and cooling demand of a standard German house, can hold stable temperature throughout, has fresh, filtered air and no condensation or mould issues (unlike our old house which was a condensation factory in winter).
Features of house include:
• Slab has foam insulation around and under it
• Ground floor has straw bale walls – made in “SITUP” panels from Huff’n’Puff of Ganmain. Provide around R6 insulation value.
• Upper walls are 140mm stud walls with R4 high density batts
• Roof will have blow-in insulation (R7)
• All walls and ceiling wrapped with breathable membrane and carefully taped to ensure air-tightness.
• The exception to this will be some straw bale walls which will have breathable natural lime render.
• Gaps in construction (e.g. between window frames and wall framing) were carefully filled with insulation, including with a natural timber felt product. These gaps are often left as is in normal construction
• Triple glazed windows with air-tight seals from Logikhaus
• Large windows to the north for winter solar gain.
• Exterior blinds to reduce summer solar gain
• Heat recovery ventilation system
• 11 kW solar system
• Heat pump hot water system
• Double storey to allow more access to northern sun and to reduce footprint on block (leaving space for chook yard and veggie garden)