7 ms·

The freezer drawer on the bottom style of combination fridge/freezers is actually significantly less efficient (10-25%, depending on the model) than the freezer

The freezer drawer on the bottom style of combination fridge/freezers is actually significantly less efficient (10-25%, depending on the model) than the freezer on top style.

jayknight 4y ago
Can you explain why? I haven't been fridge shopping in about 15 years, which probably means that I will have to sooner or later. That style seems more convenient to me, but I also value efficiency.
- joxel 4y ago
  Gravity pulls the hot air down into the bottom freezer
  - cies 4y ago
    Time to read up on that...
- iam-TJ 4y ago
  Assuming the reference is to an upright fridge/freezer with the fridge compartment above the freezer compartment, one reason for less efficiency might be that the freezer has to contain a fan to push the cold air up to the top of the fridge compartment where it falls to the bottom of that compartment. If the freezer compartment were above the fridge I'd assume it could mostly rely on gravity. There is also sometimes a stepper-motor controlled baffle to open/close the link between the two - closed when the freezer is cooling - it usually opens around -18C when freezer temperature is heading lower. That baffle will also close in frost-free freezers whilst the heater element is melting the ice on the evaporator - it usually reaches +20C and happens several times a week.
- JshWright 4y ago
  It has to do with the arrangement of the compressor. The compressor generates a lot of heat, and is located at the bottom of the appliance. With a bottom freezer, that means the compressor is much closer to the freezer and it's much harder to keep that heat out of the freezer.
  - bombcar 4y ago
    Household fridges/freezers are really hampered by the built-in compressor. Much could be saved by using remote compressors but that cost is much higher and usually associated with commercial units.
    - Scoundreller 4y ago
      Especially if you’re in a hot climate. Maybe one day we’ll have a refrigerant network in a home that refrigeration could tap into, but the cost of specialization will probably exceed the savings :( Or maybe run a municipal water loop into the fridge? Many are almost there when they have an ice machine (which is also horrible for efficiency).
      - bombcar 4y ago
        Or in a cold one - it strikes me as some variation of insane that I have a box in my house that heats the room by trying to freeze the contents when it is -30º outside.
        Scoundreller 4y ago
        You fundamentally misunderstand your matryoshka doll of insulated boxes! In winter, you don’t want to bring in very cold stuff from outside the big box into a smaller box inside the big box: the net effect is you’re making the overall big box colder. Heat pumps are very efficient! Though your argument holds up if electricity is expensive and heat is cheap (e.g. off grid with woodstove heat) If anything, you want to bring stuff from outside the big box, put it in the little box to chill further (dumping the heat inside your big box), and then toss out the super chilled stuff from the little box out of the big box.
        bombcar 4y ago
        What I want to do is put the little box outside the big box in winter, though I suspect all the "waste heat" the freezer/fridge "burns up" offsets the gas used to heat the house somewhat. All in all it's too complicated to work out, but I will admit to leaving frozen goods in the trunk in the winter because of laziness.
- tonic5 4y ago
  Combined fridge/freezer units use a heat pump to get the freezer really cold and residual cold air is cycled into the fridge. So having the freezer on bottom is not the optimal design, maybe because cold air is dense and will fall taking more active effort to distribute it. Source: https://youtu.be/CGAhWgkKlHI https://youtu.be/CGAhWgkKlHI
scarby2 4y ago
> actually significantly less efficient It's less energy efficient. It's significantly more time efficient and ergonomic.

The freezer drawer on the bottom style of combination fridge/freezers is actually significantly less efficient (10-25%, depending on the model) than the freezer on top style.

jayknight 4y ago

Can you explain why? I haven't been fridge shopping in about 15 years, which probably means that I will have to sooner or later. That style seems more convenient to me, but I also value efficiency.

joxel 4y ago
Gravity pulls the hot air down into the bottom freezer
- cies 4y ago
  Time to read up on that...
iam-TJ 4y ago
Assuming the reference is to an upright fridge/freezer with the fridge compartment above the freezer compartment, one reason for less efficiency might be that the freezer has to contain a fan to push the cold air up to the top of the fridge compartment where it falls to the bottom of that compartment. If the freezer compartment were above the fridge I'd assume it could mostly rely on gravity. There is also sometimes a stepper-motor controlled baffle to open/close the link between the two - closed when the freezer is cooling - it usually opens around -18C when freezer temperature is heading lower. That baffle will also close in frost-free freezers whilst the heater element is melting the ice on the evaporator - it usually reaches +20C and happens several times a week.
JshWright 4y ago
It has to do with the arrangement of the compressor. The compressor generates a lot of heat, and is located at the bottom of the appliance. With a bottom freezer, that means the compressor is much closer to the freezer and it's much harder to keep that heat out of the freezer.
- bombcar 4y ago
  Household fridges/freezers are really hampered by the built-in compressor. Much could be saved by using remote compressors but that cost is much higher and usually associated with commercial units.
  - Scoundreller 4y ago
    Especially if you’re in a hot climate. Maybe one day we’ll have a refrigerant network in a home that refrigeration could tap into, but the cost of specialization will probably exceed the savings :( Or maybe run a municipal water loop into the fridge? Many are almost there when they have an ice machine (which is also horrible for efficiency).
    - bombcar 4y ago
      Or in a cold one - it strikes me as some variation of insane that I have a box in my house that heats the room by trying to freeze the contents when it is -30º outside.
      - Scoundreller 4y ago
        You fundamentally misunderstand your matryoshka doll of insulated boxes! In winter, you don’t want to bring in very cold stuff from outside the big box into a smaller box inside the big box: the net effect is you’re making the overall big box colder. Heat pumps are very efficient! Though your argument holds up if electricity is expensive and heat is cheap (e.g. off grid with woodstove heat) If anything, you want to bring stuff from outside the big box, put it in the little box to chill further (dumping the heat inside your big box), and then toss out the super chilled stuff from the little box out of the big box.
        bombcar 4y ago
        What I want to do is put the little box outside the big box in winter, though I suspect all the "waste heat" the freezer/fridge "burns up" offsets the gas used to heat the house somewhat. All in all it's too complicated to work out, but I will admit to leaving frozen goods in the trunk in the winter because of laziness.
tonic5 4y ago
Combined fridge/freezer units use a heat pump to get the freezer really cold and residual cold air is cycled into the fridge. So having the freezer on bottom is not the optimal design, maybe because cold air is dense and will fall taking more active effort to distribute it. Source: https://youtu.be/CGAhWgkKlHI https://youtu.be/CGAhWgkKlHI

scarby2 4y ago

> actually significantly less efficient It's less energy efficient. It's significantly more time efficient and ergonomic.