How the cost estimate works
KilnCost models a firing as three phases: a bulk climb (110°C/h for bisque, 160°C/h for glaze — calibrated against Skutt's published FAQ examples), a final 100°C ramp at your chosen Orton speed, and any hold time. Energy is kilowatts × hours × an estimated duty cycle (how much of the firing the elements are actually drawing power), which mirrors the "adjustment factor" in Skutt's own published cost formula.
Duty cycle is an estimate (0.60–0.65 for glaze, 0.40–0.45 for bisque depending on brick thickness) calibrated to bracket Skutt's own worked examples — it is not a manufacturer-published constant, and actual duty cycle varies by kiln condition and ambient temperature.
Sources
Questions
What formula does this calculator use?
kW × total firing hours × duty cycle = energy in kWh; energy × your electricity rate = cost. Firing hours come from the Orton cone chart's ramp-rate columns plus an estimated bulk-climb rate.
Why is duty cycle an estimate?
No manufacturer publishes a duty-cycle table. Skutt's own FAQ gives two different adjustment factors (0.5 and 0.7) for the same kiln and cone, so KilnCost uses the calibrated midpoint and always labels it an estimate.