Green EnergyEnergy that fits in with the ecosystem

if one uses straw bale walls and frost protected shallow foundations what saving is possible on 135sqm house?

I’m looking at building a 135 m sq, 4 bed house in cornwall. I want it to be energy efficient (carbon neutral if possible), reduce construction pollution as much as possible and keep construction costs relatively low. The average price of construction of a similar size property using conventional materials is around £91,000 according to my research. what kind of saving (if any) would I make using the above materials and any other environmentally friendly money saving materials?

I have seen buildings like this on T.V, trace architects of those for info

Efficient Building Scheme 2010

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