Clive and Ruth Aims' cob cottage is warm in winter and cool in summer.
Yesterday, they opened their cottage off SH3 to a steady stream of visitors eager to see the fundamentals of building a cob house.
They also charged a small fee, which will go toward an earthquake-strengthing report for St Mary's at Upokongaro.
Mr Aim said living in an earth house had a ``satisfying, nice feel to it''.
``I love it. It feels really comfortable,'' Mrs Aim said.
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The internal walls were good with humidity, and because they were able to breathe, they were a buffer to heat and moisture, and kept the house dry.
He demonstrated how to make cob using 40 per cent shellrock fines and 60 per cent clay _ ``very forgiving stuff'' _ which the couple gathered on their land.
Their 15 solar panels meant the couple could live off the grid.
The power was stored in batteries and when there was enough power, the panels stopped producing. Since October 2010, the panels had produced 4000 kiloWatt hours.
Their hot water was heated by a wetback and they cooked on the woodstove.
Building cob was labour-intensive and their wheelbarrow was testament to that, having carried 80 tonnes of cob to build the lower storey of their house.
The Aims decided to build their cob cottage after visiting Mrs Aim's brother's mud-brick house in Tasmania.
Building cob was not as labour-intensive as mud-brick, and the cob won out.