Have you ever wondered how much it costs to fire your electric kiln? It is something you should know, especially if you are wanting to make a profit on your wares and even when reporting your taxes. It is relatively easy to do if you are armed with the appropriate information. It is a simple formula.

FORMULA

Cost per kilowatt hour
X Kilowatt rating of kiln
X Program duration (hours)
X Cycle of kiln
= Cost of firing load

HOW TO FIGURE YOUR COSTS

1. To figure cost per kilowatt hour, you can either call your provider, or check your bill. Every provider has a varying rate unless you locked in to an agreed upon amount usually annually. This can range by area and time of year.

2. You can figure the kilowatt rating of your kiln with information that is located on the electrical data plate which will be on the side of the control box on your kiln (see photo top right of page). The data plate will show the volt/phase/amp and watt capacity of your kiln. The watts could be from 1600 to 1800 on a small 120v kiln, 5000 to 8000 watt for a medium 220v kiln (18-23 wide). Some of the larger kilns can be as high as 11,000. Convert the watts to kilowatts by dividing by 1000. Therefore, 8000 watts would equal 8.0 KW.

3. Your program duration is the number of hours your kiln is engaged ie actually turned on to complete its firing cycle. If you have digital controls, the actual time will be displayed at the end of a firing cycle. If you do not have digital controls, figure the time when you press the start button until it shuts off (watch the clock and reduce it by number of hours left on your timer at shut off.)

4. The duty cycle is the amount of time that the kiln is actually using electricity. The elements do not consume electricity the entire time you fire. If you listen while it is firing you can hear a pulsing of off/on as the elements draw power to heat- that is the relays drawing and stopping power. Most generally, this rate is about 50-60 percent of the amount of time the kiln is going through its cycle. For sake of argument, consider the cycle to be 60 percent consumption. So if your firing program is 7-8 hours, your consumption rate will be about 4.5 hours give or take a bit. For sake of this discussion, we will presume it to be 60 percent of 8 hours.

Using the above information you, would use the formula like this:

Cost per KWhour $.49
X KW rating 1.8
X Program duration 8 hours
X Program cycle 60 percent
$4.23