If you are trying to find our how many amps does a refrigerator use over time, the easiest way to find out, is to google your refrigerators model number and see if it has an Energy Star rating. If it has an energy star rating they usually list it out per year.
Example: 350KWH per year (that is 350,000 Watts hours per year)
Using the Energy Star Rating to figure out the average power consumption:
If you take 350,000 and divide it by the number of days in a year (365) that will give you 958.91 watt hours per day (350,000/365=958.91wh)
If you divide 958.91watt hours by the number of hours in a day (24) you get 39.96 average running watts (958.91/24=39.96)
If you divide the running watts by the voltage you will get the amps (Watts/Volts = Amps). Most refrigerators in the US and Canada run on 120 volts, so you take the 39.96 average watts and divide that by 120 volts you will find that the refrigerator averages .34 amps. (39.96/120=.34)
If your refrigerator does not have energy star rating (which most vaccine and commercial refrigerators do not) you will either have to contact the manufacturer of the refrigerator (who may have this information) or purchase a KWH meter. Having a KWH meter would give you a more precise measurement anyway.
An energy meter is a great easy way to measure your appliances power consumption. This works by plugging the meter into the wall outlet and then plugging the refrigerator into the meter. The meter will calculate the amount of power it device is using over time.
These meters are generally inexpensive and actully may same you money on your electric bill by helping you become more aware of how much power your applinances are using.
Link on the side of this page will direct where you can purchase one of these. The meter you purchase will likely come with user instructions, but they are generally very easy to use.
Why is it usally so much less than the nameplate rated amperage?
The nameplate amperage is the amount of amps the appliance pulls when the refrigerator’s compressor is running. The compressor cycles on and off making the average way lower than the running value. The average will vary with the insulation value in the refrigerator.
Refrigerator amps is the amount of electrical current it’s compressor uses to cool it’s compartment. Amperage for most household refrigerators, is anywhere from 3 to 5 if the voltage is 120. A 15 to 20 amp dedicated circuit is required because the in-rush amperage is much higher. The average amperage is lower because the compressor isn’t running all the time, this is often measured in kilowatt hours KWH.
If your fridge does not have an Energy Star. Try doing a calculation using the nameplate amperage:
Basing a calculation based on the refrigerators the nameplate amp rating is more or less an educated guess. Each refrigerator has different efficiency levels. Typically a refrigerator runs on 35% duty cycle, (65% for a freezer) meaning that if you take that nameplate amperage and divide it by 35% you can get an idea as to how much power the average running amps will be.
How this will help you purchase the right size your battery backup system?
Once you know the average running watts, use our battery bank calculator to find out how large your battery backup system will have to be to power your refrigerator over time.