120v versus 240v kiln

[Val]

I checked the archives but can't find the answer to my question.

I have been told that a 120v kiln is more of a draw on elecricity than a 240v, and that the 240v is more efficient. Are there any electricians our there who can answer my question. I have a 240v now and was thinking of getting a 120v

[Larry Lunsford]

For the same wattage, a 240V device will be slightly more efficient than a 120V device. This is due to the 120V device drawing more amperage which means you also have more power loss in the wires leading to the device (kiln or whatever). The difference in efficiency will be very small and not something worth worrying about.

More important is what power hook up options do you have and will a 120V kiln be adequate for your needs. Most 120V kilns are also intended to run on a normal household circuit of 20 amps maximum. Bigger kilns will require 240V and possibly more than 20 amps.

Larry

[Val]

Thanks Larry, that helped to confirm what we thought might be the case.

Val

[Bert Weiss]

Val

To expand on what Larry wrote- The key calculation is watts per cubic foot. Volts times amps = watts.

A 120 volt kiln can only heat so much space. If the box is too big, it can not reach fusing temps.

I am actually not so sure which calculation is more important, watts per cubic foot or watts per square foot. Either way there is a point where it won't work.

[Mark Wilson]

the efficiency of a 110v and a 220v kiln are exactally the same, no difference. what you might be refering to is the fact that you need less current with the 220v kiln. for example, if i wanted an 1100 watt kiln, it would take 10 amps at 110v or 5 amps at 220v. electrical power in watts is the product of voltage and current P=I*V, so with a higher V you need less I to get the same P. that has nothing at all to do with efficiency which has everything to do with insulation.

[Phil Hoppes]

I did an analysis on this before so you might check the archives. Most household panels/wiring is either 14 gage for lights and 12 gage for the garage. 12 gage 110v is good for 20amps. If you don't wish to rewire, you are then limited to about a 2.2KW kiln. Depending on the insulation of the kiln the size may vary but lets assume your design runs about 850W/cuft. This would make the max size kiln on a 110V 20A circuit of about 2.5cuft. This would be a kiln a little smaller than 18"x18"x14".

If the kiln is insulated more it may be a little larger. Insulated less, then it will be smaller.

Phil

[charlie]

I checked the archives but can't find the answer to my question.

I have been told that a 120v kiln is more of a draw on elecricity than a 240v, and that the 240v is more efficient. Are there any electricians our there who can answer my question. I have a 240v now and was thinking of getting a 120v

doubling the voltage allows a halving of amperage. to carry the increased amps, you have to increase the thickness of the wires. thicker wires have a greater efficiency.

thus, yes, a 240v will be more efficient, electrical-wise, than a 120v. it's not very significant over a period of a single firing, but over a period of years, it is.

[Val]

Thanks for all the replies they helped me decide on my second kiln. Decided on 240v

Original is a 240v and I was thinking about a 120v but wanted lower electric bills over long term ( always thinking about long term)