You need something with high thermal mass that’ll take up space – jugs or bottles of clean water is a good option. Just remember to keep their lids or corks on, to prevent the water from evaporating.

I did read somewhere – I think it was in a make-your-own-fridge tutorial, can’t find the link now – that beer supposedly has better thermal mass than water, so maybe a few sixpacks at the back of your fridge will do the job even better. I haven’t tested this myself, though.

If I stacked the fridge with all the food I could buy, but still there’s plenty of room, what else can I fill (not overstock) the fridge with?

This post was mentioned on Digg by daria79: Great post, good tips!…

When you open your freezer (or refrigerator, the same principles apply to both), the cold air will “slide” out of it at the bottom of the opening, while air at room temperature will enter at the top. This room tempered air has to be cooled to keep the freezer at the right temperature.

If the freezer is already full of frozen items, the heat in the room tempered air will be absorbed relatively quickly by these. Which means your freezer has to spend less energy cooling it down.

If the freezer is empty, or nearly so, it won’t get much help cooling the room tempered air down. So it has to spend more energy to maintain the proper temperature.

Plus, if there’s a lot of empty space in your freezer there will be more room for the warmer air to fill.

So putting in stuff to keep the freezer full might be worth it if you open it relatively often.

What you have to take into account, though, is that when you put those milk jugs and soda bottles in there, the freezer has to spend a chunk of energy to cool them down. If you open your freezer kind of rarely, you might not “earn” that chunk back.

Please note that the above applies to freezers that have their door on the front, ie. that open like a refrigerator.

If you have chest freezer with a lid on top, freezing extra stuff almost certainly isn’t worth it.

The reason for this is that due to the fact that warm air rises and cold air doesn’t, a chest style freezer will lose very little of its cold air when it’s opened.

Yanic