Fridge/Freezer power consumption analysis

Chrysalis

Thought would post this for informational reasons.

Manufacturers currently give very vague information on power efficiency levels of units.  Armed with a smart meter, and a watt meter, I did compare my old tesco fridge to my new hi sense fridge.

The new fridge is about 25% taller, with similar depth.  The old fridge had a manual dial in the fridge as its only controls, the new fridge has independent settings for freezer and fridge, an eco mode and a super freeze mode, new fridge has led bulb vs standard in old fridge, new fridge has auto defrost, vs manual defrost in older fridge.

Old fridge about 15 years old consumed 75w when cooling, and a little over 10w for its light.

New fridge consumes about 60-65w when cooling (moves around) and about 1.2w for its light.

New fridge is on defaults of -20C for freezer and 4C for fridge.

However the old fridge had much longer periods not cooling, approximated looking at smart meter data about 45% on, 55% off.  New fridge is closer to 85% on, 15% off a considerable difference, it seems to struggle, as its not close to its max settings.

Looking at overnight power data for 30min intervals, my consumption with old fridge on typically went 0.05,0.07,0.05,0.07 with the occasional 0.05 as a 0.06. (this is consumption for my entire home).

On the new fridge its a consistent 0.07,0.07,0.07 and so on.

The old fridge not only was off more often but its on off periods lasted in excess of 30 minutes so cycles was visible on smart meter data, this unit cycles at much smaller intervals.

However instead of evening out at perhaps 0.06,0.06, they are almost all 0.07.

Note all these figures are kw/h 30 minute intervals.

This is roughly about an extra 480w per day consumption.  So disappointing to see modern units havent progressed in this area, but also that its actually considerably worse proportionally than the old unit.

Now I also have watt meter data as a reference to compare against, the old fridge in its last 3 days of use was using around 420w a day, the new one just over 920w a day.  Ambient temps rose yesterday, so no Monday data included in this. Over year if this was sustained as an average would be about 153kw on old unit and about 336kw on new unit.

At 20p per kWh, an annual cost of around £84 for old unit and around £184 for new unit.

QrizB

I'm surprised that your new fridge freezer is so power-hungry.

What's the model? What does the energy label say re. annual energy use?

km1500

have you used a fridge thermometer to check the fridges are cooling to the same temperature

markin

Self defrost and bigger. What was the old annual kwh on the label?

MultiFuelBurner

It makes sense to me our older (left by previous owner beko freestanding fridge freezer 50/50 split we measured that at approx 200kwh a year).

Replace by our larger integrated Samsung Fridge Freezer 70/30 split and 30% larger capacity. This is going to use 330kwh a year approx

I wonder if the split of fridge and freezer effects. For example the larger the fridge section which is opened more and needs more cooling that the freezer.

Zandoni

Surely the only way to tell is to have individual watt meters on each plug, with the same contents in each unit and the same ambient temperature.

Chrysalis

Zandoni said:

Surely the only way to tell is to have individual watt meters on each plug, with the same contents in each unit and the same ambient temperature.

Well can never satisfy perfectionists, but the conditions are not far off that, ambient temp within 1C, similar food and amount of it.  Same watt meter used on both, same smart meter used on both.

Chrysalis

km1500 said:

have you used a fridge thermometer to check the fridges are cooling to the same temperature

No, but I think the new unit is cooler, as can feel it simply by opening the door.

This was never meant to be scientific quality report, just a analysis of what I have observed.  As very little info like this is out there on the net, I thought some would be interested in it.

Chrysalis

QrizB said:

I'm surprised that your new fridge freezer is so power-hungry.

What's the model? What does the energy label say re. annual energy use?

I dont think is anything on the label, but there is a rated annual usage somewhere (might be the manual) I will post this tonight for you along with model.

dunstonh

We changed to a Samsung American FF last year.    Set to 4c for fridge and -18c for Freezer (20c is too much).  It uses about 0.65kWh per day.        Ice maker use seems to be a key influence.   External temperature doesn't have as much impact as it did on our old model which used 3 times more energy.

deano2099

We had an old fridge freezer left by previous owners in for a month or so when we bought our current property. We had it turned on as decorators were using it, but replaced a few weeks before we moved in. The smart meter data showed the base load of the house drop about 30% when we replaced it, even though it was replaced by a bigger model. New one definitely more efficient for us.