How much does a kiln firing cost?
Between the myth of the “ruinous kiln” and the denial of “it costs next to nothing”, there is a simple calculation few potters actually do. This tool prices each firing with YOUR kiln and YOUR tariff — so firing finally makes it into the price of your pieces.
Firing cost
9.10(your currency)
- Energy used
- 36.4kWh
The method
The kiln’s plate states its maximum power — what the elements draw while heating. But they do not heat continuously: the controller switches them on and off to follow the firing schedule. Over a full firing they work 60–80% of the time; that is the duty cycle.
Energy used is therefore: power × duration × duty cycle. Cooling is free — the kiln is off, merely giving its heat back.
Cost comes from multiplying by your kWh price, the one on your bill, in your own currency — the result comes out in the same one.
In the formula: P the power (kW), t the duration (h), d the duty cycle (%), k the kWh price.
energy (kWh) = P × t × d / 100 · cost = energy × k
Good to know
- Duty cycle rises as elements wear and insulation tires: a kiln that “struggles to reach temperature” runs at 100%… and costs accordingly.
- A well-packed kiln costs barely more than a half-empty one: the load matters less than the walls. Firing full divides the cost PER PIECE.
- Off-peak tariffs are worth the shift: scheduling the bulk of the heat-up overnight saves 20–30% on every firing.
- Bisque heat-up must stay slow to drive off water (200 °F/h at first): shortening a firing to save money explodes pieces — the savings live elsewhere.
- The plaster for your molds is calculated in this same category.
FAQ
- What does a typical firing cost?
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With a 6.5 kW studio kiln, an 8 h glaze firing at 70% duty uses about 36 kWh. At €0.25/kWh that is €9; at a US average of $0.17/kWh, about $6. A small 3 kW kiln runs $4–5 per firing. Far from the horror stories — but not free either, especially doubled (bisque + glaze) per batch.
- How do I find MY kiln’s duty cycle?
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Three methods, in rising accuracy: estimation (70% for a healthy kiln), listening to the relay clicks over an hour (on-time / total time), and direct measurement with an energy meter on the kiln’s circuit — the one investment that gives the exact figure, firing after firing.
- Bisque or glaze: which firing costs more?
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Glaze, usually: the end temperature is higher (cone 6 vs cone 06), and the last few hundred degrees are the priciest — the hotter the kiln, the faster it loses heat. Bisque partly compensates by lasting longer (slow ramp). Both can be priced here by changing duration and duty.
- Does better insulation really change the bill?
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Yes, through the duty cycle: a modern fibre kiln holds its schedule at 55–65% duty where an old dense-brick kiln demands 80–90%. On weekly firings, the gap funds part of a new kiln within a few years — it is the spec to examine when buying, before power.
- What do “cones” mean versus temperature?
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A pyrometric cone measures heat WORK (temperature × time), not temperature alone: cone 6 falls at 1240 °C on a fast ramp, but as low as 1220 °C on a slow one. For cost, only duration and duty cycle matter — but for your glazes, trust cones over the display.