Issues Calculating Electric Kiln Costs Len Wemer is a name familiar to many in the clay community. He began with a career in mining engineering and then went on fo produate studies in geology. He has extensive experience in a number of fields and holds all sorts of technical certifications and licenses including that ofanairplane pilot. But what makes him invaluable tothe ceramic community is his knowledge af kilns, He took over the McLennan kin building business anumber of years age and is the one stop shop for many of mer technical needs regarding electric kilns and elements. When asked recently how to calculate the cost of firings, this was Ais response; Calculating the cost of running an electric kiln is actually far easier than one would think. It starts with the cost of electricity. In BC, at the moment, it costs 5,77 cents per kilowat- hour in a residence. There are small variations in commercial rates, but any kiln being run at home is paid for at this cost. What that means is that for every kilowatt of power the kiln consumes, it will cost 5.77 cents each hour, if it’s on all the time. Or, put in terms of a 10,000 watt kiln (10 kilowatts), every hour that it's full on (all switches on high), it will use 57.7 cents worth of electricity. Ten kilowatts is what | use in a 7.2 cubic foot 909 round kiln, for example, so to be able to run a kiln that size for an hour for a cost of 58 cents is quite a good deal. To calculate the cost of an entire firing requires either some careful recording, or a dam good guess. [tend to like the darn good guess if it's so close as to avoid a lot of needless recording of numbers. As an example, think of a fictitious, but probably typical, cight hour bisque firing in a 10 kilowatt kiln. The first two hours will be with the kiln switches on bow, or at, say, 25% power. The power it will consume is: 2 hours X 10 kw X 0.25 X 5.77 cents/kwhr = 28.85 cents Then tum it to medium, or 50% power, for another 2 hours, the power consumed ts: 2 hours X 10 kw X 0.50 % 5.77 cents‘kwhr = 57,7 cents. Then if you tum it to medium-high for another 2 hours, or 75% power: Zhours X 10 kw X 0.75 X 3.77 cents/kwhr = 86.55 cents Then on high (full power) for another 2 hours: 2 hours X 10 kw X 1.00 X 5.77 cents = $1.15 Nothing left to do but add those all up: $0.29 + $0.58 + $0.87 + $1.15 = $2.89 For a different kiln or firing cycle, just change the appropriate numbers, either power or time spent at that power setting. Feel free to make it as complicated as you like (i.e. 5 or 6 different settings instead of 4), and of course keep track of the price of electricity. I've always figured that a glaze firing in a kiln that size (10kw) takes about 34.00 worth of electricity, so about $3.00 worth for a bisque firing sounds about nght. If you compare that to the effort required to stoke a wood-fired kiln for $ hours, electricity really sounds like it’s presently an inexpensive form of energy, which is probably why we're looking at price increases in the near future. At this time of year, having the kiln in the basement and venting only the fumes outside sounds like a good idea, because the $3.00 or $4.00 worth of energy you're putting into the kiln will eventually all still be in the howse by the time the kiln is cool inside again after a firing. Where else could it go? And, for the rest of the year, I hope the idea of a 5° kiln wall as compared to a 2.5" wall makes sense to a lot more kiln purchasers! Len Werner January 2003 Potters Guild af British Columbia Newsletter Gallery of BC Ceramics 2003 Exhibitions January no show February In Praise of Hands: BC Instructors’ Show February 6 - March 3 Opening night February 6, 6-8pm March Flores Rachelle Chinnery March 6 - 31 Opening night March 6, 6-8pm April Hazardous Amraction Lewis Krzyczkowski April 3 - 28 Opening night Apeil 3, 6-8pm May Rebecca Robbins May 1 - June 2 Opening night May 1, 6-8pm June Keith Rice-Jones June 5 - 30 Opening night June 5, 6-8pm July Serving tt Right Maggie Kneer and Clive Tucker July 3 - August 4 Opening night July 3, 6-8pm Angust Rhythm Joanna Copp August 7 - September | Opening night August 7, 6-8pm September Ornithikes Gillian McMillan September 4 - 29 Opening night September 4, 6-8pm October Beneath the Surface Nicole Riedmueller October 2 - November 3 Opening night October 2, 6-Bpm November Deb Taylor November 6 - 25 Opening night November 6, 6-8pm