This fan lists its "Max. Amperage" as 3.2. I assume the motor draws that much when it's first turning on, then settles down to some lower current. How much current should I expect it to draw when it's running steadily?

I ask because I want to know how a) how much this will cost me to run for a month continuously, and b) how much it will heat the space. I'm figuring that all the energy the motor draws gets swiftly converted into heat. Please correct me if I am thinking about this incorrectly.

2 Answers 2


You can't determine the actual amperage from the maximum. If the manufacturer did not provide this information (which is usual) your best bet is to use a device like a Kill-A-Watt (disclosure: I have no affiliation with this product nor have I ever used it, the name just stuck in my head). This device plugs into the wall and you plug the appliance into the device. It measures the amperage that the appliance draws.


The reason you are only provided with the maximum is that you are expected to run it with a controller, which could allow you to run at anywhere from 0 to 2500 rpm (the rated maximum) and the current and power will vary depending on how fast you want the fan.

I think you are mistaken about the energy becoming heat aspect though - this is not a heater. While there will be some thermal losses (as no motor is 100% efficient) the majority of the energy goes into moving air.

  • Right, but as that air settles down, losing energy to friction with itself and the walls, won't it get converted to heat? Where else would would that kinetic energy go? Jun 1, 2012 at 15:05

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