Understanding the cost to fire your kiln
There is a common misperception that electric kilns for ceramics are expensive to operate. However, when
compared to gas kilns and other factors, this is not necessarily the case. Below is a simple method to
calculate the cost of running an electric kiln.
Key Information:
To determine the cost, you need answers to three key questions:
- What is the Kilowatts usage of your kiln?
- The electricity consumption of your kiln is expressed in kilowatts per hour (kW/h). This information is typically
found on an information plate on the kiln, e.g., 6.6 kW/h or the Amps the kiln uses. - If you have the total Amps of your elements, use the following calculation: 1 Amp = 0.22 kW/h. For example, if
your kiln uses two 15 Amp elements (total 30 Amps), the calculation would be 30 x 0.22 = 6.6 kW/h. - If the above information is not available, a good kiln manufacturer can provide an estimate based on the
internal dimensions of the kiln.
- The electricity consumption of your kiln is expressed in kilowatts per hour (kW/h). This information is typically
- What is the cost of electricity per kilowatt-hour (kW/h)?
- You need to know the cost per kW/h, which can be found on your utility bill (e.g., Eskom, COJ). This cost
typically ranges between R2.10 and R3.20 per kW/h, depending on the supplier.
- You need to know the cost per kW/h, which can be found on your utility bill (e.g., Eskom, COJ). This cost
- What is your firing time?
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- Know the duration of your firing program. Most ceramic programs run between 8 and 10 hours. Note that the
firing time is not the same as the time your elements are actually on and consuming electricity. A good
estimate is that your elements are on for approximately 70% of the firing cycle time.
- Know the duration of your firing program. Most ceramic programs run between 8 and 10 hours. Note that the
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Cost Calculator
Use this simple calculation to work out the cost of a firing.
Consumption (kW/h) × Cost per kW (R) × Firing Cycle Time (hours) × 70%=Cost of Firing (R)
Examples:
1. For a 30 Amp kiln:
6.6kW × R2.30per kW/h × 8hours × 70% = R85.00
2. For a 40 Amp kiln:
8.8kW × R2.30per kW/h × 8hours × 70% = R141.68
3. For a 45 Amp kiln:
9.9kW × R2.30per kW/h × 10hours × 70% = R159.39
By understanding and applying these calculations, you can accurately estimate the cost of firing your
electric kiln and see that it may be more affordable than you previously thought.