Fridge temperature

[Squirrel]

Does a fridge or freezer require more power to keep the food cold when it is nearly empty or packed full? At first I thought it would be more efficient when empty because there is less mass to keep cold. Then I thought about when the door is opened and closed ' this would let a lot of warm air into an empty fridge but very little into a full one. Strange question; does anyone know the answer or does it depend?

[sft42]

Fridges and Freezers work more efficently when full for the very reason you have suggested secondly...once the things inside are cold (or frozen) then only the introducion of warm air as you open the door will raise their temp....in a full space there is less air let in.

[answerbok]

That old chest nut Squirrel, or even upright; [next you'll be saying which freezes fastest, a cup of hot water or a cup of cold water?] Depends entirely on how often the door is open. A full fridge (or freezer) has more thermal mass, and less air to rush out, so it's a good idea if the door is opened frequently. If the door is rarely opened ... packing it full might reduce internal convection, saving loss at the walls, but otherwise, not much difference...

[Janetex]

Less energy is required to maintain the temperature of objects than to maintain air temperature.

[Squirrel]

Thank you for your answers - now I know I really can ask anthing on this site and still get a perfect answer to it.