A small electric kiln uses about 1,700 watts, a midsize kiln runs between 6,000 and 11,500 watts, and a large studio kiln can pull 17,000 to 23,600 watts. But wattage alone doesn’t tell you the full story. What really matters for your electric bill is how many kilowatt-hours (kWh) a firing consumes, which depends on kiln size, target temperature, and how long the firing takes.
Wattage by Kiln Size
Electric kilns span a wide range of power draw. At the small end, test kilns and tabletop models like the Skutt Micro Scarab pull around 1,650 watts, roughly the same as a space heater. These plug into a standard outlet and fire small batches of test tiles or jewelry-scale work.
Midsize kilns designed for home studios and classrooms typically draw between 6,000 and 11,500 watts on a 240-volt circuit. A common residential workhorse like the Skutt KM-1227 pulls 11,520 watts and needs a 48-amp dedicated circuit. Smaller models in this range, like the KM-818 at 6,400 watts, can run on a 30-amp circuit with a standard 240-volt outlet (NEMA 6-50).
Large production kilns jump to 17,000 watts and above. The biggest single-phase models reach 23,600 watts and draw up to 80 amps, requiring hardwired connections rather than plug-in receptacles. These are studio and small-business machines, not something you’d casually install in a garage without an electrician and a panel upgrade.
How Much Energy a Single Firing Uses
Wattage tells you the rate of electricity consumption. To find the total energy a firing uses, you need to account for time and duty cycle. Kiln elements don’t run continuously during a firing. They cycle on and off as the kiln controller maintains its programmed temperature ramp. As a general rule, elements stay powered for roughly half to three-quarters of the total firing time.
Here’s a practical example: a kiln rated at 10,800 watts fires for 5 hours. That’s 10.8 kilowatts. Multiply by 5 hours and you get 54 kWh if the elements ran nonstop. But since they cycle, you’d use closer to 27 to 40 kWh for that firing, depending on how well insulated the kiln is and how high the target temperature goes.
Real-world measurements back this up. Oxford Clay, a UK-based pottery studio, measured their energy-efficient kiln at approximately 19 kWh for a bisque firing and 40 kWh for a glaze firing. That’s a significant difference, and it comes down entirely to temperature.
Bisque vs. Glaze Firing
Bisque firings (the first firing of raw clay) typically reach Cone 04, around 1,060°C (1,940°F). Glaze firings go higher. A mid-range stoneware glaze firing to Cone 6 hits about 1,220°C (2,230°F). That extra 160°C requires substantially more energy because the elements must work harder and run longer against increasing heat loss at higher temperatures.
The Oxford Clay data shows glaze firings using roughly double the energy of bisque firings. This ratio holds reasonably well across different kiln sizes, so if your bisque firing costs $3, expect the glaze firing to cost around $5 to $7. Every piece you make goes through both firings, so budget for both when estimating your per-piece costs.
How to Calculate Your Firing Cost
The formula is straightforward:
- Step 1: Divide your kiln’s wattage by 1,000 to get kilowatts. A 9,460-watt kiln equals 9.46 kW.
- Step 2: Multiply kilowatts by the total firing hours. If the firing runs 8 hours: 9.46 × 8 = 75.7 kWh at full power.
- Step 3: Multiply by 0.5 to 0.75 to account for element cycling. Using 0.6 as a middle estimate: 75.7 × 0.6 = 45.4 kWh.
- Step 4: Multiply by your electricity rate. At $0.16 per kWh (near the U.S. average): 45.4 × $0.16 = $7.26 per firing.
Your electricity rate is on your utility bill, usually listed as a per-kWh charge. Rates vary enormously by region, from around $0.10/kWh in parts of the South to $0.30/kWh or more in California and the Northeast. That single variable can triple your firing cost for the same kiln and the same work.
What Affects Energy Use the Most
Kiln size is the obvious factor, but several others shift your electricity consumption significantly.
Loading density matters. A full kiln uses essentially the same energy as a half-empty one, because most of the energy goes into heating the kiln chamber, the shelves, and the furniture, not the pots themselves. Oxford Clay calculated that a single dish accounts for only about 1.54 kWh across both bisque and glaze firings, a small fraction of the 59 kWh total. Firing a full load spreads that fixed energy cost across more pieces, dropping the per-piece cost dramatically. Half-empty firings are the biggest energy waste in most studios.
Kiln condition also plays a role. Worn elements draw more power and take longer to reach temperature. Cracked or missing lid bricks leak heat. A kiln that used to finish a Cone 6 firing in 8 hours but now takes 11 is using meaningfully more electricity, and likely needs element replacement.
Firing speed is a tradeoff. Slower ramp rates keep elements on longer but at lower duty cycles. Very fast firings blast the elements at full power. In practice, the total kWh difference between a fast and slow firing to the same cone is modest, maybe 10 to 15 percent. The bigger factor is simply what cone you’re firing to.
Electrical Requirements for Installation
Most kilns beyond the tabletop size need a 240-volt circuit, the same type used for clothes dryers and electric ranges. The amperage and breaker size depend on the kiln’s wattage.
Midsize kilns in the 6,000 to 11,500 watt range typically need a 30 to 50 amp breaker and a NEMA 6-50 receptacle. Larger kilns above about 14,000 watts often require direct hardwiring to the panel with breakers rated at 60 to 80 amps. An electrician can assess whether your existing panel has capacity for a new high-amperage circuit or whether you need a subpanel.
Three-phase power, common in commercial buildings, doesn’t change how many watts a kiln uses. A three-phase kiln consumes the same energy as an equivalent single-phase model. The advantage is that three-phase wiring uses thinner conductors and smaller breakers for the same wattage, which reduces installation costs. Some utilities also charge lower rates for three-phase service.
Monthly Cost Estimates
For a home potter firing a midsize kiln (around 11,000 watts) twice a week, with one bisque and one glaze firing, expect roughly 60 to 80 kWh per week. At $0.16/kWh, that’s $10 to $13 weekly, or $40 to $52 per month. At $0.30/kWh, the same schedule runs $72 to $96 monthly.
A busy teaching studio or production potter firing a large kiln four to five times a week could easily use 200 to 400 kWh weekly, putting monthly kiln electricity at $130 to $500 depending on local rates. At that volume, firing efficiency, packing kilns full, maintaining elements, and avoiding unnecessary firings, starts to meaningfully affect your bottom line.