Indoor / outdoor temperatures

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Note that the internal temperatures (red) are relatively constant at around 20 C,

while outdoor temperatures (blue) fluctuate wildly from 0 to 32 C.

Specs

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Efficient - financially

The total energy bill for this 450 sqm home is an average of $255 / month

(hot water, heating, lighting, cooking etc).

A standard sized 200 sqm thermahome's total energy bill would be around $125 / month.

 

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Efficient - thermodynamically

The walls are 250 mm deep with an R rating of 8 (3 times the recommended insulation rating).

The ceilings have extra batts giving an R value of 4 and 5 in bedrooms and living rooms.

It's 20 degrees inside all year round, with a thermal gain of around 4 degrees C daily.

 

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Efficient - environmentally

The higher insulation value means less energy used.

We removed 9 trailer loads of rubbish in the whole build.

And we used any left over insulation in the garage ceiling.

And most materials are recyclable.

 

• A high insulation / low waste solution compared to standard buildings.​

 

• Walls can be fire-proofed polystyrene insulation (Xflam) or standard EPS (fire rated expanded polystyrene) with factory painted steel internal and external layers. The surfaces can be painted after installation.

 

• Polypanels have been used in construction for 30 years and meet residential insurance criteria. Extra sound proofing can be easily added and is recommended between bedrooms.

 

• Approved by council – meets all Building Code requirements.

 

• Some engineering required for structural and bracing calculations.

 

• Major residential prototype finished in Taupo - see gallery.

 

• 3 times the recommended insulation – warmer in winter, cooler in summer.

 

• In-concrete underfloor heating (hydronics), sourced from a 14 kW air-to-water heat pump which is sufficient (due to the high exterior insulation value), even though it is 2/3 the recommended size for the area as per ALF (Annual Loss Factor) calculations.

 

• Lower relative humidity means healthier and more comfortable living, with less associated health problems.

   

• Quick and easy to construct.

 

• Less tradesmen to organise – no lining, gibbing, painting, cladding, weather proofing.

 

• Minimal waste - 10 cubic metres for 450 sqm house compared to 50 for a 200 sqm house.