Comparing Bisque and Glaze Firing Electricity Costs
For any ceramic artist running an electric kiln, electricity is the largest recurring operating expense. The Bisque vs. Glaze Firing Cost Calculator estimates and compares the electricity cost of each firing type based on your kiln size, peak temperatures, firing duration, and how often you fire each month. For example, a standard 7 cu ft kiln fired at cone 6 (2,232 °F) costs roughly $2.25 per firing at $0.12/kWh — a small number that compounds to nearly $110/year for a studio running four glaze firings per month.
The Formula Behind the Firing Cost Estimate
The calculator estimates kiln energy consumption using a rule-of-thumb formula that accounts for kiln volume, peak temperature, and firing duration. The energy usage (kWh) is proportional to both kiln size and the temperature it must reach — larger kilns and hotter firings draw more power.
bisque kWh = kilnSize × (bisqueTemp / 1000) × 1.2 × firingHours / 8
glaze kWh = kilnSize × (glazeTemp / 1000) × 1.2 × firingHours / 8
The cost per firing is then simply the kWh times your electricity rate:
bisque cost per firing = bisque kWh × electricityRate
glaze cost per firing = glaze kWh × electricityRate
Annual costs are derived by multiplying the per-firing cost by the number of firings per month and by 12 months:
annual total = (bisqueCostPerFiring × bisqueFreq + glazeCostPerFiring × glazeFreq) × 12
The ratio shows how much more expensive glaze firing is relative to bisque:
glaze vs bisque ratio = glazeCostPerFiring / bisqueCostPerFiring
And the estimated batching savings applies a 15% reduction to the annual total:
est. savings if batched = annualTotal × 0.15
Worked Example: 7 cu ft Kiln at $0.12/kWh
A pottery studio owner has a 7 cubic foot electric kiln and pays $0.12 per kWh. They fire bisque at 1,835 °F and glaze at 2,232 °F, with an average firing cycle of 8 hours, and run 4 bisque and 4 glaze firings each month.
- Bisque kWh: 7 × (1835 / 1000) × 1.2 × (8 / 8) = 7 × 1.835 × 1.2 = 15.41 kWh
- Glaze kWh: 7 × (2232 / 1000) × 1.2 × (8 / 8) = 7 × 2.232 × 1.2 = 18.75 kWh
- Bisque Cost / Firing: 15.41 × $0.12 = $1.85
- Glaze Cost / Firing: 18.75 × $0.12 = $2.25
- Annual Bisque Cost: $1.85 × 4 × 12 = $88.80
- Annual Glaze Cost: $2.25 × 4 × 12 = $108.00
- Annual Firing Cost: $88.80 + $108.00 = $196.78
- Glaze vs Bisque Ratio: $2.25 / $1.85 = 1.22x — glaze costs 22% more per firing
- Cost Difference: $2.25 − $1.85 = $0.40 per firing
- Est. Savings if Batched: $196.78 × 0.15 = $29.52
This studio spends about $197 per year on kiln electricity, and could save roughly $30 by consolidating partial loads into full firings.
Practical Application Context
Understanding per-firing electricity costs helps ceramic studios make better operational decisions. A studio running many small bisque loads can often batch two half-loads into one full load, cutting bisque firings in half and saving $50–$100 per year with no change in output. For studios considering upgrading to a larger kiln, this calculator can model the trade-off: a 10 cu ft kiln costs more per firing, but if it allows fewer total firings, the annual cost may actually decrease. Glaze firing temperatures also matter strategically — artists who can achieve their desired surface at cone 6 rather than cone 10 will see a meaningful reduction in electricity cost for every glaze firing they run.
How professionals interpret bisque vs. glaze firing cost output
Experienced ceramicists and studio managers look at the Glaze vs Bisque Ratio first. A ratio near 1.0x means bisque and glaze firings cost about the same — unusual and worth investigating (it might mean bisque temperatures are set too high). A ratio of 1.2x–1.4x is typical, reflecting the difference between cone 04 and cone 6 temperatures. Ratios above 1.5x often indicate that glaze firings are reaching cone 9–10, and the studio may want to explore whether lower-fire glazes could achieve similar results. The Annual Firing Cost is then compared against studio revenue — for a working production potter, kiln electricity should represent no more than 3–5% of gross revenue. If it climbs above that, it signals either under-pricing, over-firing, or inefficient kiln loading. The Est. Savings if Batched number is treated as a planning benchmark: if the potential savings exceed the hassle of holding work to fill a kiln, batching is worth the scheduling adjustment.
