Zig-zag kilns offer a 15-20% reduction in Specific Energy Consumption (SEC) and up to 75% reduction in SPM emissions over FC-BTK. A higher percentage of Class I bricks are produced as compared to FC-BTK (80-85% Class I bricks as compared to 55-60% in FC-BTK). There is an option for easy retrofit of FC-BTK to natural draught Zig-zag kiln. Savings from reduced fuel consumption and increase in revenue due to the higher percentage of Class I bricks. The capital cost of retrofitting of existing FC-BTKs ranges from INR 10-25 lakhs and pays back in 3 months-2 years. However, for new construction, the capital cost ranges from INR 35-45 lakhs natural draught kiln and INR 40-45 lakh for a high draught kiln. The payback period for the new construction of the Zig-zag kiln is 2-3 years.
Zig-zag kiln required skilled manpower for its operation. However, the same workforce working in FC-BTK can be easily trained for operating Zig-zag kilns. 4 persons are required for firing at a 6-hour shift.