How can I calculate the electric consumption cost for a vending machine with the following information...

Question

This is what the plaque on the side says:

9 amps

115 volts

60 cycle

1 phase

...cost of electricity here is $0.094/kWh. Vending machine runs 24 hours a day outside in Albuquerque, NM area. Model is "Vendo 407".

Answer 1

With that sort of power input I'd assume the machine contains refrigeration equipment. While the machine may be on 24 hours a day, the refrigeration compressor will cycle on and off to maintain temperature, so simple knowing the nameplate rating does not tell you the actual power requirement.

Still, outdoors in NM, the compressor might be running most of the time, so 9 * 115 / 1000 will give you a approximation of the power in kilowatts, just about 1 kW, so it will cost about $0.094 per hour or about $2.25 per day, or  about $70 a month. However, while the compressor may run most of the time, it won't be running literally all the time so the cost will in fact be less, but it is hard to say how much less without actual measurements. There are inexpensive devices available for measuring the power consumption over time, the Kill-a-Watt™ is one, there are others.

Answer 2

The Department of Energy did some testing on the energy efficiency of vending machines.  In one week the Vendo model consumed 38 kWh.  On am monthly basis, that works out to be 38 kWh x 30/7 = 163 kWh.  

The machine being tested was inside a building.  Your outdoor location in New Mexico will have a higher consumption.  Let's round up the usage to 200 kWh for simple math.

200 kWh x $0.094 / kWh = $18.80 per month.

The Kill-a-Watt device is a great way to measure the actual consumption.  It measures volts, amps, power factor, etc.  If you leave it plugged in, it will register the kWh consumption.  You can find the device for less than $20 on the internet.