Kill A Watt - odd results for my refrigerator

[wahoowad]

Got my new Kill A Watt (P3) in the mail the other day. Plugged in my fridge to see what my running wattage was. I could hear the motor running but it was only showing around 200 watts. I expected it to be more around 1000 watts so I let it run and checked it periodically.

After 36 hours it only showed 2.6 kwh which also sounds low. The motor cuts on a lot more than it used to (fridge is 1997 vintage) so I was expecting to see it using a lot of power. It is doing a decent job keeping the contents cold/frozen so I know the compressor is running. Sort of seems like the motor must be cutting on some times but not necessarily the compressor? I have yet to see it pulling the 1000 watts or so it must use when operating the compressor.

This morning I watched it after I had opened the door a time or two for breakfast. The motor cut on but it only showed 166 to 200 watts. My voltage and frequency is fine (121v, 59.9 hz). I'd think the compressor was not working right except my inside temps are good. I'm confused.

 

[blujacket]

Most of the power drawn from a refrigerator is during the defrost cycle. You'll see the biggest power consumption in the summer time from the excess humidity.

 

[Highbeam]

I have found the same results. I logged just over 4 kWH in 2 days which is 40 cents. The fridge is super cheap to run even if you log kwH for a week so the defrost cycle might draw a lot but it is for a very short time.

It is NOT worth it to buy a new 1000$ fridge to save energy unless your current one dies. Look elsewhere for savings.

 

[BrotherBart]

Yeah mine rang in at just over 3 KWH per day on the Kill-O-Watt and it was made in 1985.

 

[Highbeam]

Instead of propoganda from various manufacturers and gov't groups that all benefit from us purchasing new appliances, nothing beats actual measurement of the device. We've all measured 20-30 cents per day for even the old refrigerators. That's 6-9$ per month, say 7.50. A new modern fridge costs about 1000$, even if it was magic and didn't use any electricity it would take 133 months to pay for itself. 11 years!

 

[fbelec]

the older ones did take a little more than the new ones do, but nothing to write home about. that 200 watt reading is it. i've put my amprobe on a circuit when the refridge got restarted after being off for 4 hours (did a circuit panel change) and it was drawing about 1.8 amps. that's common. i tested a fridge from the early 50's the one that has the freezer in the fridge one door for both that thing was quiet no fans running in it. it was drawing 2.1 amps

 

[Gooserider]

You should probably see a big spike when the motor fires up, but the actual running power is pretty low... However the Kill-a-watt doesn't record peak draws, just average, so it won't show the spike... About the only way you'll see it is if you have a meter that actually does record peaks and holds them...

As to the motor and compressor - in a fridge, the two are one unit, if the motor is running, so is the compressor...

Gooserider

 

[fbelec]

some side by side fridge's the fans are separate. when the fridge section calls for cool it turns on a fan that draws from the freezer section with out turning on the compressor. if the freezer section calls then the compressor and both the fans in the freezer and the fan across the condenser come on

 

[Highbeam]

I've also got a seperate fan on my 90s era standard fridge. The coils are under the fridge so the fan draws air up through the coils only and has no coolant connections.

Motor and compressor are most likely combined somewhere else. Running watts on any compressor/pump are pretty low and that peak surge is not really important since it is so short.