How Much Insulation Pays in a Small Brick Kiln: A Thickness Rule Balancing Fuel Saved Against Blanket Cost

This paper addresses small updraft and downdraft brick kilns that lose a large share of their fuel heat through uninsulated walls. It presents a wall-insulation sizing rule for intermittent brick kilns, derived entirely from stated assumptions and a computation whose code and full output accompany the paper. The sweep covers blanket thickness from 0 to 100 mm. The headline outcome is: best x 38; best annual total usd 916; uninsulated annual total usd 1382.4; annual saving usd 466.4; fuel per firing at best kg 181.8; fuel per firing uninsulated kg 432. These figures identify a specific operating point or bound that a workshop can apply directly, and they also show how quickly performance deteriorates away from it. No kiln was built, no ware was fired, and nothing was measured for this study. SIMULATED, NOT MEASURED.