According to a test report by Stiftung Warentest (the German equivalent to Consumer Reports), my vertical fridge consumes ~ 0.4-0.5 kWh / day. While that is more, it's nowhere close to the 10x-20x given by this guy.
At its core a refrigerator is a big insulated box with a heat pump and a heater. Manufacturers have optimized the living daylights out of these things. Big manufacturers (LG, Whirlpool, GE) have tried at various points to roll out more and more efficient compressors going back to the 80s. And they've all had a horrible time of it. There's not as much room for optimization with the heater, but most manufacturers have moved towards electronically controlled heaters that can run on demand instead of on a timer – works well until a thermistor fails. Samsung also tried to "optimize" the defrost heater by shrinking it (my impression is LG is that just as guilty of this) and you'll find plenty of complaints about problems with the evaporators icing up.
Anyhow, out here, at least, smaller fridge/freezers including chest freezers are so-called manual defrost units and do not have a power hungry heater. If I had to guess I'd say the big difference consumption is due more towards running a giant heater in the back (a.k.a. auto defrost) than the overall size.
According to the government site responsible for energy ratings - energyrating.gov.au, ‘Refrigerators and freezers have been required to display an energy label since 1986 and to meet minimum energy efficiency levels since 1999. As a result, refrigerators and freezers are now 70 per cent more efficient than they were 30 years ago’.
New technology also mean that internal sensors inside the fridge can regulate the temperature so that the fridge is always running efficiently. Other innovations include temperature warnings and electronic temperature controls, humidity controlled compartments, and different temperature zones within the fridge according to the food to be stored. There are also ‘vacation’ settings which lowers energy consumption for the duration of your trip - you just need to remember to switch the setting off when you get home.
Today every new fridge carries a red-star energy-rating sticker, giving it an efficiency rating and telling you how many kilowatts (kW) of electricity it uses in a year, given average usage. While energy-efficient fridges might cost more they can save tonnes of greenhouse gas emissions and hundreds of dollars over their lifetime through lower energy use. For instance, a 400 litre family fridge with a maximum six-star energy rating can use as little as 250 kW per year and cost you about $40 a year to run. A less efficient 500 litre model, on the other hand, could use 650kW a year and cost you more than $100 a year to run. That's a saving of $60 a year or $600 over ten years. And with electricity prices set to rise substantially in coming years, savings are likely to be even greater.
https://hipages.com.au/article/energy_efficient_fridges_and_...
Stateside the yellow "EnergyGuide" stickers were required by federal law beginning in 1980. These cover things like water heaters, fridges, dishwashers, and air conditioners.
FWIW my one fridge is around 538 liters (~19 cubic feet) and is rated at 420 kWh/year ($50/yr at $0.12/kWh). Of course I'm not sure how the testing methodology compares to that of Oz.
It’s an insulated box, like a battery, but they don’t take advantage of time of day electricity rates when they’re perfectly suited to that.
Would be unfortunate for ice cream; but for everything else in my freezer, send it to 0 Kelvin.
This made me think. I would kind of expect the energy consumption of a fridge to be related to the surface area of the cooled volume rather than the volume itself. It's not necessary to spend any energy cooling air that is already surrounded by equally cold air.
Assuming all fridges are cubes, doubling the volume of the fridge will increase the surface area by a factor of 2^{2/3} = 59%. This will also be true if the fridge has any rectangular dimensions and you double the volume by scaling it up evenly in all three dimensions.
Things are more complicated if you scale the dimensions of the fridge unevenly.
You don’t have to assume any shape for this, as long as the shape remains the same, and that it is not fractal. You could have a spherical fridge and it would still be true.
Why assume that the old fridge will be geometrically proportional to the new fridge? I think that's particularly unlikely to be true in the case of a person replacing their existing refrigerator.
I'd expect that for a fridge that's permanently closed, but what if you open it regularly? I'd expect a lot of the cold air inside (so volume) to mix with the room-temperature air once you open it..?
They are. Unless you reach the scale of the walk-in fridge, you don’t want a fridge to be deeper than an arm’s length, and even small fridges have that depth because they’re designed to fit a kitchen top, which also is scaled for an arm’s length.
Vertical scaling is a bit more flexible, but will stop at about 2 meters (until you reach sizes that you can drive a forklift in)
On the plus side, if you scale things evenly, wall thickness also goes up, so heat losses per m² of area will go down.
Then there's variability depending on thermal conductivity and specific heat capacity of various foods. So what you're trying to calculate is heavily dependent on the actual contents, not just surface area.
Of course, fridges have cycling behavior similar to an AC that turns on as soon as temp dips below a set temp, but has a window of sorts. Making the above math even more complicated.
This assumes that the dominant energy expenditure of the fridge is bringing new food down to fridge temperature.
But almost all of the contents of a fridge have been in there for a while and are already at fridge temperature. Most of what the fridge is doing is maintaining the internal temperature against the outside environmental temperature.
I don't like the idea of American fridges, they waste lot of space on the separator middle wall, I think the best compromise who is not fine with regular fridge are now a bit wider fridges but with single vertical door.
My Chinese in-laws have vertical fridge which has 3 sections, top regular door fridge, middle drawer which goes directly outside (not sure whether it's chilled or frozen), no need to open anything and bottom freezer with door.
We have these in the US.
We also have some with a door-on-a-door for the fridge portion, so you can grab e.g. a can of soda or some mustard out of the inset door which only accesses a little storage on the door itself, without opening the entire fridge.
Neither is as common as other styles (the latter especially—that's kind of a gimmicky expensive-fridge feature) but they exist.
This was probably true up until the 90s. At that point side by sides became pretty popular with the left side being a freezer and the right side being a fridge, full height. See:
https://www.bestbuy.com/site/ge-25-1-cu-ft-side-by-side-refr...
After these broke the trend of the top freezer, other styles became more popular. These days one of the most popular style is the "french door" where there are two side by side doors for the fridge compartment up top with a drawer below for the freezer.
https://www.bestbuy.com/site/lg-26-5-cu-ft-french-door-count...
Top freezer fridges these days are often seen as a very outdated and out of fashion style of fridge usually only relegated to the bottom tier models of fridges. If you go into most appliance stores you'll see row after row of french door, several side by sides, and then a couple of super basic top freezers.
Personally, IDGAF about "style" for a fridge when it comes to door arrangements. I like my side by side the most as then I have both fridge and freezer items as convenient heights instead of only really having a freezer at eye level and having to duck down to grab anything in the fridge.
A modern house conditions the air inside to a certain temperature (often heating it up) and then has a box inside that is conditioning the air (often cooling it back down to outside temperature).
If you have an empty fridge or freezer, it's a good practice to put e.g. water bottles in there for cool thermal mass, ideally in the top (cold air flows downwards; old fashion fridges were cabinets with a compartiment in the top for blocks of ice they would store underground in winter).
To be fair, prices come in kWh, so it makes sense in order to ask "how much do I spend in a day"