izatsoe says:

I think you meant a combination refrigerator-freezer.

The term “frost-free” only applies to the FREEZER. I have a freezer attached to my refrigerator, which is frost-free, but I also have a freezer in the garage (no refrigerator) which is not frost free. Some call it “manual defrost”.

Every time you open the door to a freezer, at least SOME air comes in. ALL air contains some water in the form of water vapor (a colorless gas, not droplets). But the warmer the air is, the more water it can contain.

When it gets into the freezer by the open door, after it closes, that air cools down, and so it can no longer contain as much water as it had outside, in the warm house. So, that water must go somewhere. And it does – it condenses into LIQUID water inside the freezer on the surfaces of all the food, and on all the walls of the freezer and everything else in there.

THAT is what we call frost, and that’s where frost comes from.

In my freezer, I have to just deal with it. It builds up until it looks like winter in Canada in there! Just today I had to scrape some of the “snow” off (the frost off) just to get an ice cube tray to lay flat!

So, it gets to the point where it needs to be removed, or else eventually the entire freezer would be filled with snow and there would be no more room.

Long before it gets to that point, I take out any remaining food (I kinda plan it so that I eat all I can and buy much less for the freezer prior to this time) and then unplug the freezer and let it melt. Sometimes I get impatient and position a blow dryer or heater blowing into it. Gottta be careful though, it gets wet all around as the ice and snow melt, and of course, electricity and water can be dangerous together. So don’t put the heater or blow dryer inside, or down where it can get wet.

There is so much water melting and coming out, it would make a big puddle in my garage if I did not have a pan and a hose to catch and redirect the flow of melting water.

After it all melts, the inside looks like a brand new freezer, and I plug it back in and put all the frozen food back in. When I open the door a few times, within a day or two, *sigh* I can see a slight layer of frost building up already, and the process repeats.

Inside in the kitchen my refrigerator has a frost-free freezer attached. It requires no such work… it stays free of frost all the time, all by itself.

Advantages/Disadvantages:
Obviously this is a lot less work. No planning involved. But how does it do that? Easy – the freezer actually has a HEATER inside it, which comes on twice a day and warms up the air inside the freezer (amazing, huh?) just enough to MELT away the tiny layer of frost that formed since twelve hours ago. This water evaporates and is vented out of the freezer.

BUT, you mentioned energy efficiency – this comes at a tremendous cost, one being the energy it takes, not only to run a heating element (always inefficient and costly) but worse, to run the refrigeration system extra hard to keep the freezer frozen, and make up for the heat from the heating element!

All just so that you never have to empty it and defrost it. But wait. there’s more – there is another big difference.

You see, this little layer of frost also forms on your food. Then, every time that heater kicks on in there, it also MELTS a tiny layer of the surface of that food. Unless that food is both wrapped air-tight AND insulated, the heat will melt the food juuuust a little.

No biggie if you bought a steak today, or ice cream, and you’re planning on eating it within a few days.

Longer than that and things change. If I buy a box of ice cream, or popsicles, they are going out in my NON-frost-free freezer. Why? It takes only a couple days of melting-heating and they start to turn to garbage. But in the frosty freezer,they stay excellent indefinitely – MONTHS of perfect popsicles, ice ceam, everything.

Other foods are affected too. Meat in the typical store wrap has clear plastic over it (so you can see what you’re buying, I guess). That clear plastic offers almost no protection from the melting and refreezing that goes on, so after a few days, it gets what they call “freezer burn”, not a burn at all but an outer layer of destruction, and if enough, bad-tasting meat when you cook it.

Meat goes outside in Mr. Frosty as well, at my house.

So what goes in the inside, frost-free freezer? Not much. It makes ice cubes, and they would get smaller and icky-er every day, but I use them up. If they sit too long, I throw the whole bucket out and let new ones get made overnight (I am talking about an automatic ice maker, of course).

I have some frozen dinners in there, but if I really cared about them, they should be out in Mr. Frosty.

If I had to pick only one, I’d get frosty, not frost-free, unless I could always eat all the food within a week. Frost-free means the same thing as auto-defrost.