Which takes more energy to keep at a given temperature, a full refridgerator or an empty one?
Thanks for any input!
Assuming you have a fairly new refrigerator, there wouldn’t be much difference in energy usage once the contents have reached the equilibrium point. The two main factors would be how often you open the door and the temperature of items being put into the refrigerator. If you took two of the same model refrigerator, one empty and one full, and let both sit for a month unopened, the energy usage should be the same except for the time it takes the full one to cool its contents to the given temperature.
I think the question you might want to ask, is which refrigerator would take longer to reach a specific temperature…the full one or the empty one? And the answer would be the full one…if they started out at the same temperature to begin with.
I think the point of the question is not a comparison of cool-down times between the two, but a verification of the old saw that a full refrigerator is less expensive to run than an empty one. I believe this is true primarily as a result of opening the door: the emptier the refrigerator is, the more cold air can fall out every time the door is opened, and thus the more warm air needs to be cooled down once the door is closed.
Realistically, I suppose the comparative energy efficiency depends on how often the door is opened, how long it stays open, and how often items are removed and replaced. However, if everything else is the same, a full refrigerator ought to be more efficient than an empty one due to the reason cited above.
They’re probably very close, but the empty one should use more energy. With the fridge full, it will take longer for the temp to change, up or down, because of the added mass. That will make the on/off cycles needed to maintain a given temperature longer in duration, and fewer in number. The cycles should be less efficient at startup than when running continuously.
empty fridge = more on/off cycles = more energy used.
Well, if its the full one, it will take more energy to keep all the stuff cold, AND because its full, you will be in and out of it alot…
The empty one wont need as much energy because you wont be opening the door so much to an ‘empty’ refridge. [grin]
I have a fridge in the garage and kitchen [both same size], the one in the garage keeps my Pepsi’s colder cause i only store soda’s and film in it, the Pepsi’s in my kitchen fridge arent as cold cause [i beieve] the frequency of an opened door, and amount of other food stuffs in there and the fridge has to work harder to try and keep all that stuff cold.
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The greatest power loss for a freezer or refrigerator is rechilling after the door is opened. All the cold air, being heavier than the the warm room air, falls out on your feet pretty quickly. The bags of frozen chicken parts, broccoli, and UFO pilots stay where they are while the door is open. Thus they stay cold, and they don’t have to be rechilled. Chest-type freezers are a different deal. Cold air doesn’t fall out of them, so the fullness wouldn’t make much of a difference. In an upright freezer, I’d keep empty boxes in any vacant space to keep the boxfuls of cold air from falling out.
If the fridge in your garage keeps the beverages colder, it’s probably because its thermostat is set a little lower. A little twist of the knob could turn the lettuce in the kitchen into green slush.