In the spring of 2006, I had an electrical meter connected by a certified technician from the local power company. This meter was set inline between my kiln and the breaker box and was separate from the main meter, so it recorded only the power used by the kiln. During that time I performed firings in the high, middle, and low temperature range to calculate what different firings were costing me.
These firings were performed in a 7 cu.ft. L&L JD230HD with:
- Single phase/240v
- Computer-controller w/ “type S” thermocouples,
- 3″ K23 softbrick (walls, floor, and lid).
- Standard (small) gauge elements… which were not new, but not worn out either. They had eleven firings (four ^04 bisques, and seven peaking at 2345-2355F) total on them when the meter was hooked up.
The meter was zero’d out prior to installation, and I kept track of the energy consumption by photographing the dials as reference.
Firing 1: Peak at 2345 F Hold for 2 minutes + 5 hours of holds b/t 2000 and 1900 F.
Reading: 87 Kw.
The national average for a kilowatt hour was 9 cents,
87kw/h x $0.09 =
Firing 2: “Fast Glaze” program to ^018 (1384F).
Reading: 104 kw/h - 87 = 17 kw/h used.
Firing 3: 270F/hr to 2000F.
Reading: 139 kw/h - 104 = 35 kw/h used.
There were seven firings total, all yielding the same costs (give or take a few cents) per firing.
It would have been nice to see what the difference was in terms of new elements vs. the ones at this stage –and even vs. aged elements (although I rarely let mine get that far gone). But since this meter was on temporary loan from the power company, I was still interested in seeing these readings, and I think they may represent the longest stage in terms of the elements lifespan.