Help Me Understand My Old Fridge Power Consumption

• 

  highon2str on 18/02/2015 - 11:26

  My 7yo fridge consumes 1.4 kWh a day. My entire property consumes about 10kWh/day. The fact that your 1 fridge is consuming more power than my entire property means you either have a monster of a power hungry fridge, or there is something wrong with the meter.

  Have you tried plugging it into something else and measuring it?

  • 

    Pielo on 18/02/2015 - 12:19

    Im going to wait until the fridge has been plugged for 24h (around 5pm this afternoon) and I will read the Kwh for those 24h.
    I will try plugging another device in the meter after 5pm, to check it. A lamp for example?

• 

  c64 on 18/02/2015 - 11:31

  the fridge will need to run a bit initially to cool it down from room temp.

  fridge size and season will also be other factors. large fridge sizes & warmer seasons will consume more electricity. you might also need to fine tune the thermostat.

  possibly your meter measurements are inaccurate.

  the energy sticker on your new fridge should give you an indication of its running cost per year.

  • 

    Pielo on 18/02/2015 - 12:17

    Sorry about the confusion: I am still using my old fridge. The new one is supposed to be delivered this weekend. I am trying to find out how much power my current (30yo) fridge is using.

    I have edited my first post.

• 

  digitalterrorist on 18/02/2015 - 11:32

  Your current fridge based on the readings probably consumes 9Kwh per day.

  However don't read too much on the new fridge's label. You have to understand how that number is arrived at.

  The more frequently you open a fridge door, the more coolness is lost and the fridge's compressor has to worker harder and longer to get the temperature down.

  I have no idea how they test new fridges for a rating. Do they start it up and let get to optimum temperature first, then start the measuring for a few cycles while the door is never opened? Or do they let it go through a defrost cycle as well, do they open the door at set intervals to mimic real world conditions. Who knows. I think the 384kwh per year is a bit optimistic.

  Other things you need to take into account when comparing, size of fridge, size of freezer compartment, does one have auto defrost/frost free features. Also are your seals on your old fridge in good condition?

  so nothing like comparing apples with apples.

  • 

    Pielo on 18/02/2015 - 12:17

    My current fridge (also referred to as the old fridge) is a frost-free 460L fridge. The seals are in "okay" conditions: They are not broken or damaged, but they dont stick very well anymore.

• 

  battler on 18/02/2015 - 11:37

  2pm-5pm is in the hottest part of the day. Old fridge may have had compressor running during a large part of that time.
  To compare a 3 hour period of actual recording on your plug in device to a sticker is not entirely accurate, but nevertheless indicative.
  To be a bit fairer, take a 2 day reading of old fridge and then new fridge using same device, then compare.

  Bottom line is your 30 year old fridge is horribly inefficient and should be punted.
  The savings would pay for the new fridge in just a few years, if not less.

  You may be eligible for a buyback/rebate on disposal of the old fridge:
  http://www.actewagl.com.au/Save-energy/Free-energy-services/…
  (or just gumtree it)

  • 

    Pielo on 18/02/2015 - 12:30

    Sorry about the confusion: I did not setup the time on the meter, so 14:30 is after 14 hours and 30 minutes being plugged (the time started at 00:00 when I fist plugged the fridge).
    I plugged the fridge yesterday at 5pm and read the meter this morning at 7:30am.
    The second reading was at 10:30 this morning.

    In 4h30min (at 5pm this afternoon), the fridge will be plugged for 24 hours straight. I will post a reading then.

• 

  pjetson on 18/02/2015 - 11:56

  First of all, does the fridge compressor ever turn off, or is the fridge making a noise 24/7?

  Cheap energy meters are often quite inaccurate, but usually mostly for low power load. Try connecting a 100w incandescent globe to it (if you have one!) instead of the fridge and see what it says.

  The sticker on your old fridge says 240V 1.7A which is presumably a maximum power draw. This is about 400 watts maximum.

  Your new fridge is 3 stars and 510 litre. This web site http://www.ausgrid.com.au/Common/Customer-Services/Homes/Ene… suggests that it should draw about 690kwh a year, or almost 1.9kwh per day.

  5.4Kwh over 14.5 hours is about 370 watts, and 6.5kwh over 17.5 hours is also about 370 watts, so the energy meter at least seems consistent. Those figures suggest almost 9kwh per day - about 5 times what the government suggest. Therefore, something is horribly wrong.

  It's possible that the temperature of your new fridge has not settled down yet, so the compressor may be working harder than it would normally run. You might also be opening the door too much.

  Do you have a thermometer that you can put inside the fridge? If not, you can get one from Bunnings for a couple of dollars. Put it inside the fridge and then look at it first thing when you get up in the morning. The fridge should be more than 0 degrees and less than 4 degrees. The freezer should be about negative 18 degrees.

  You could also try zeroing the power meter when you go to bed and then reading it first thing in the morning, to find out how much it is drawing overnight when the doors are shut tight.

  • 

    Pielo on 18/02/2015 - 12:13

    Sorry about the confusion: I am still using my old fridge. The new one is supposed to be delivered this weekend. I am trying to find out how much power my current (30yo) fridge is using.

    I have edited my first post.

    The compressor runs most of the time. At least 3/4 of the day I would say.

    • 

      digitalterrorist on 18/02/2015 - 15:32

      Don't mistake the fan noise in the freezer section for the compressor noise. I have a 15 y/o Kelvinator going strong and the freezer compartment fan runs more often than the compressor.

• 

  c64 on 18/02/2015 - 13:06

  a heavy compressor duty cycle suggests it is not working efficiently (possibly needs a regas, but this is not economical)

  what does your electricity box meter tell you over a time period? turn off all other heavy electricity slurping items for greater accuracy.

  anyway, you will find out when you receive your next electricity bill. a big drop will tell you your old beast was unhealthy.

  • 

    Pielo on 18/02/2015 - 13:33

    I live in an MDU, and the electric box meter is closed. I dont have a key, I went to the Strata Management, they dont have a key either, only ActewAGL apparently.
    If I want to see the meter, I have to pay a $70 fee, for one of their employee to come.

    • 

      c64 on 18/02/2015 - 13:35

      that sucks :)

    • 

      MasterScythe on 18/02/2015 - 15:08

      It's always a shame when 'kids' vandalize the locks on those boxes isn't it?

    • 

      ozzie freddo on 19/02/2015 - 12:24

      Ask your supply company (not your retailer) if they can give you web monitoring of your meter (assuming you have a smart meter…but if it is locked up you may not know what sort you have…but ask anyway).
      I am supplied by Ausnetservices and they have a very friendly web interface that lets me see historical (beyond 6 hours old) graphical information down to a 30 minute resolution…. no more worrying "did I leave the iron on" when I'm on holidays. I can check from anywhere in the world.

• 

  digitalterrorist on 18/02/2015 - 15:41

  Something doesn't look right with that 502W and 3.6A readouts.
  The old fridge label says it's rated at 1.7A, now at 240V, that equates to 408W max - not 502W - perhaps your meter is off. Also if you calculate at 3.6 - that would equate to 864W.
  Something is not right with the readings. Maybe take the reading after 1 min from when the compressor kicks in, sometimes there is an initial surge power to make the compressor kick over and get the gas moving.
  Maybe check the meter against a lamp with a globe with known wattage and confirm it's reading right.

  • 

    ozzie freddo on 19/02/2015 - 11:52

    Power is the product of voltage x amps x power factor, so these figures look pretty correct (from a metering viewpoint).

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  ozzie freddo on 19/02/2015 - 12:16

  My Kelvinator 480L bought over 40 years ago is still performing well. With the same sort of meter as yours it is averaging 1.240kWh per day. Idle it uses 19 watts (doing silly things like heating panels to stop condensation) and when the compressor is running it uses 135 watts.
  Your pictures indicate that your meter is OK so it is showing that your current fridge is unwell, probably low on refrigerant gas and your observation that the compressor is running 3/4 of the time indicates that it is struggling to make the low gas work.
  All in all, this makes your upgrade a wise choice.

  BTW that meter model (sold under many brands) can give very false readings for lower power electronic items as their switched mode power supplies and more complex current waveforms seem to confuse the meter.

  • 

    Pielo on 19/02/2015 - 12:40

    My meter gave me false values when first testing the fridge.

    After I tested it with smaller devices and re-plugged the fridge, I am now getting the 250 VALTac, 1.71A, 225W when the compressor is running.
    It has been plugged for 17.5 hours now and I am reading 2.7 Kwh so far. I will read the meter again tonight at 7pm, to see how much it has used in 24h.

• 

  bonezAU on 19/02/2015 - 12:45

  I recently replaced a ~15 year old Westinghouse 250L fridge with a brand new LG 515L fridge. The new fridge uses less energy and my fruit and vegetables last a hell of a lot longer in the new beast.

  Technology has come a long way it seems.