Depends on cost of raw material. If you have power plant and ash is free then cost can be as low as Rs. 1.30 per standard brick and as low as Rs. 14- 16 per 390x290x190 block . Each with strength of over 65 kg / cm2 and thermal conductivity of less than 0.65 and almost 100% resource efficient, when using fully automatic machine with UHPC technology which allows upto 94% ash as raw material in a brick or a block.