Small Residential Freezer
How would you calculate how many amp hrs would be needed to run a small residential freezer for say 12 hours with an inverter when you (with out buying it and testing it) when you have no idea how man...
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240 kWh / year sounds about right. (That likely assumes a particular ambient temperature, that it's fully loaded, that no one is opening/closing it, etc...)
The reason you can't find anything telling you how much it'll draw in a day is there are several factors that affect this that the manufacturer has no control over. The three biggest are: Ambient temperature, loading, and how often you open it.
Ambient temperature: The hotter it is in the space it's in, the longer it will have to run in order to maintain the same temperature inside. (Direct sunlight makes this many times worse.)
Loading: The ratings are typically for a freezer fully loaded with water and assume that the freezer has already obtained its operating temperature (the stuff inside is frozen). The more empty space you have in the freezer, the more it will run. Also, most people load them with things other than water; things that have less thermal mass than water. Even fully loaded it will end up running more than the estimate.
The estimate is primarily good to use as a comparison between freezer brands and models, not what it'll likely actually cost you.
Opening and closing: This also isn't in the estimate, but every time you open it, you let heat in, which the freezer than has to remove again. (How much? That depends on loading...)
Presumably you're planning to start out with the freezer already cold...
The reason you can't find anything telling you how much it'll draw in a day is there are several factors that affect this that the manufacturer has no control over. The three biggest are: Ambient temperature, loading, and how often you open it.
Ambient temperature: The hotter it is in the space it's in, the longer it will have to run in order to maintain the same temperature inside. (Direct sunlight makes this many times worse.)
Loading: The ratings are typically for a freezer fully loaded with water and assume that the freezer has already obtained its operating temperature (the stuff inside is frozen). The more empty space you have in the freezer, the more it will run. Also, most people load them with things other than water; things that have less thermal mass than water. Even fully loaded it will end up running more than the estimate.
The estimate is primarily good to use as a comparison between freezer brands and models, not what it'll likely actually cost you.
Opening and closing: This also isn't in the estimate, but every time you open it, you let heat in, which the freezer than has to remove again. (How much? That depends on loading...)
Presumably you're planning to start out with the freezer already cold...
