Chest freezer usage and buying tips please!

May 12, 2008 2:57 PM

Contemplating a chest freezer purchase. Questions about power usage, backup power, defrosting it, and choosing the right model.

I am considering buying a small chest freezer, around 5 cu ft size. I have very limited space in my house and frankly I don't need anything much bigger than that anyway. It will have to live in the garage, as there really isn't space in the house itself. So, here's some questions for you chest freezer owners.

1. I live in the San Fernando Valley, and my garage is not insulated, so the garage interior temperature reaches 90-100F during the day in summer. Is this going to make the freezer use insane amounts of electricity, or is it within normal operating range?

2. I can't find any figures in order to calculate the power draw of a small chest freezer, but in the event of a power outage, is it worth having the freezer plugged into a UPS? How long would it last? If its 5 minutes then obviously no point, but if it was a few hours...

3. Defrosting it. I won't be buying a frost-free version for food quality reasons, and I am OK with the idea that I will have to defrost it myself every so often. How often do you defrost yours? How do you go about it? Do you try and eat everything in the freezer leading up to defrost day, or do you pack the contents into coolers during defrosting? How long does it take to defrost? Any defrosting tips?

4. I am not having much luck finding a buying guide online, that lets me select the features I am looking for - 5 cu ft or around that size, NOT frost free, temperature alarm preferred, drain at the bottom for defrosting. Not sure if there are any other features I should be looking for, suggestions? Shopping tips? Personal recommendations?

Thanks!

posted by Joh to home & garden (14 comments total)

Check out THIS SITE if you click the more info tab, it shows power usage per year, among other things. looks like a good resource on several diffent brands

HERE is aniother good site

and THIS SITE says it's "All you need to Know"
good luck
posted by Mr_Chips at 3:20 PM on May 12

Here's a 5 cubic foot GE model with manual defrost.
posted by peep at 3:26 PM on May 12

You wouldn't be the first to put a freezer in a 100° F garage. But it will use "some"* power, and it won't last long out there, doing that. Small freezers, especially, are typically low cost machines with not a lot of excess insulation, so your compressor is going to be running several hours a day. Spring for the "Energy Efficient" or "Energy Star" models, if you can find any in that small size. They'll have better insulation, and more efficient motors, at least.

Even a small freezer will have power demands in excess of what any reasonable sized UPS device will supply (1/6 hp motor on some of the units I checked, equals 130 watt load). Moreover, most UPS units are designed to power resistive electronic loads, not electrical motors - a freezer motor would certainly damage most UPS units. The freezer, if full, and unopened in a power outage, should keep its contents safe for 2 to 4 hours, even in your garage. In more reasonable environments, that time could stretch to 12 or even 24 hours. Longer than that, you need to fire up a generator, to keep your food. If your unit doesn't have one, it's worth putting a freezer thermometer in there, to let you know what temperature you've got, in case of power outages.

I don't really understand your aversion to frost free models. Small freezers like that tend to be manual defrost, simply because they are made for marginal purchase, where cost is an issue. It's cheaper to build a manual defrost machine, but they aren't any better for food than frost free machines. On the cheap end of the scale, it would be hard to find an Energy Star rated model, that is also manual defrost, but if you can find such a thing, it's worth it, especially in your case (because of your hot garage location), for the extra insulation and better motor. Manual defrost machines are harder to sell used, in most areas.

The amount of frost your machine will build, and how often you'll have to defrost it will vary with how often you get into it, and how humid your area is. For an inch of frost, with the lid open on a hot day, expect a few hours of time to melt the ice, drain and clean the unit, if you throw out the ice chunks actively, rather than waiting for it all to melt and go out the drain. You'll probably need to do this every couple of months in the San Fernando valley.

*"some" power = will run frequently in heat above 80 degrees, and pull the power of 2 to 3 60 watt light bulbs when it's running. About $0.03 an hour of running operation, where I live in Florida, and we have nearly U.S. average power costs.
posted by paulsc at 3:53 PM on May 12 [1 favorite]

Paulsc, I don't want a "frost free" model because they have a tendency to dehydrate the frozen food, and also I plan to store breastmilk in it, which has a shorter lifespan in a frost free model due to the temperature cycling.
posted by Joh at 4:24 PM on May 12

Consumer Reports says the Frigidaire FFC0723D 7-cubic foot manual defrost is good.
posted by Kirth Gerson at 4:41 PM on May 12

"Paulsc, I don't want a "frost free" model because they have a tendency to dehydrate the frozen food, and also I plan to store breastmilk in it, which has a shorter lifespan in a frost free model due to the temperature cycling."
posted by Joh at 7:24 PM on May 12

Eh, not really on the dehydrate issue, any more than a manual defrost model.

Modern frost free models just manage internal air flow, and do it far better than older machines did. There is a separate chamber with the cooling matrix in it and a fan blows cold air through the cooling matrix chamber, and into the food compartment. Any water vapor ends up on the matrix by the end of the cycle, because that's where the water vapor will condense, in the air flow. During the defrost cycle, the frost free control shuts off the circulation fan and warms the matrix chamber element- leaving the frozen food frozen. The water drains off through a pipe to an external tray which is over the external heat exchanger. When the compressor starts, the outside heat exchanger evaporates the defrost water and this actually improves the overall efficiency of the system. They need a bit more of a 'brain' than conventional freezers. but the food isn't temperature cycled, and its storage life is the same as a manual defrost model, for any modern machine. The frost free environment is less conducive to bacteria growth, and eliminates odors that can form in ice coated freezers, too.
posted by paulsc at 4:50 PM on May 12

"2. I can't find any figures in order to calculate the power draw of a small chest freezer, but in the event of a power outage, is it worth having the freezer plugged into a UPS? "

Don't bother with a ups, the draw when running is too high to make it worth it. A freezer that isn't opened will keep food safe for 16-24 hours easy if it isn't mostly empty. As long as the frozen food doesn't thaw out it's safe to eat. The first thing to thaw out is frozen OJ so as long as the oj isn't liquid everything else is OK. Check when the power comes back on.

If your freezer does get below half full or so stick some milk jug or 2l pop bottles full of water into the freezer. These will act as a buffer of sorts during a power outage and they'll prevent some of the air exchange when you open the lid (because there is less air to spill out). Plus they make dandy cold water bottles or ice packs for your cooler in the summer.

"3. Defrosting it. How often do you defrost yours? How do you go about it? Do you try and eat everything in the freezer leading up to defrost day, or do you pack the contents into coolers during defrosting? How long does it take to defrost? Any defrosting tips?"

Chest freezers shouldn't be defrosted the same way as refrigerators. What you want to do is:

1. unplug the freezer
2. get your laundry baskets and transfer your food to the baskets. (coolers would work even better but most people don't have that much cooler volume)
3. cover the baskets with a blanket or two.
4. take a stiff plastic spatula (the ones for fibreglass and bondo work on cars are good for this) and scrape the frost off the inside of the freezer. Scoop it out and toss it in the sink/on the driveway to melt
5. transfer food back to freezer and plug it in.

Defrosting this way prevents the frost present inside the walls from melting. Frost melting in between the walls can rust the steel coils inside the walls. When a coil rusts through the refrigerant leaks out and your freezer stops working.

You should defrost when the frost in the second row down is 1/4 to 3/8ths of an inch deep.

"drain at the bottom for defrosting."

If you defrost as above you don't need this drain.

paulsc anytime you have air movement over a frozen solid you increase the evaporation rate from that solid when compared to still air. The mechanics of the defrost system doesn't change this. And sure a unit could be designed that doesn't heat the food in the vicinity but practically most systems have either a simple tin divider or a tin divider + a 1/4-1/2 of insulation. Neither of which is close to ideal.
posted by Mitheral at 5:23 PM on May 12

I hate chest style freezers. Items tend to fall to the bottom. An upright freezer is much more convenient. Easier to see what is in there.

A trick we use for a power outage alert is to put a handful of ice cubes in a zip lock bag. If the power is out long enough to melt the ice cubes, then you will have either water or a solid piece of ice in your baggie.
posted by JujuB at 5:26 PM on May 12

"... And sure a unit could be designed that doesn't heat the food in the vicinity but practically most systems have either a simple tin divider or a tin divider + a 1/4-1/2 of insulation. Neither of which is close to ideal."
posted by Mitheral at 8:23 PM on May 12

The "heater" element on most modern frost free systems is about the wattage of the light bulb, and about as effective, in "heating" the frozen food. Do you worry that your freezer light is going to ruin food? It warms the cooling plate a little above the melting temperature of ice, for long enough that frost condensation drips off as water. That's it. Maybe a "heater" like that would cook a pack of frozen peas, in about a decade.

You're right about the air moving over a frozen solid increasing its evaporation rate. Presumably, few people freeze unpackaged food, for sanitation reasons, but if they did, they'd notice it drying, like they'd notice ice cube shrinkage in a frost free freezer's ice maker, after coming home from a 2 week vacation. But, presumably, a chest type freezer is not going to have an ice maker, so tiny ice cube remnants shouldn't be much of a problem. OTOH, if you're tossing in chunks of frozen chum, for later, forget the frost free model. But you're gonna be spending a lot of time sanitizing that manual defrost chum pot :-)
posted by paulsc at 5:48 PM on May 12

Water vapour goes right through a plastic bag and it's tough to get a vapour proof seal on aluminum foil. Everyone has probably seen freezer burn (which is caused by the loss of moisture) even on items properly wrapped.

paulsc writes "The 'heater' element on most modern frost free systems is about the wattage of the light bulb, and about as effective, in 'heating' the frozen food. Do you worry that your freezer light is going to ruin food?"

Defrost heaters are higher wattage than a light bulb. I couldn't find specs for a 5 cu.ft. but for example the Fridgidaire 13 cu.ft. auto defrost[PDF] has a 130W heating element. And FYI the light bulb in a freezer only operates when the door is open. A defrost heater can run for as much as 20 minutes out of every 8 hours. The model above runs it's heater for 30 minutes for every 12 hours of compressor run time.

PS: Joh the owner's manual for that freezer indicates that'll it'll keep stuff frozen for at least the normal 24 hours as long as you don't open the door during a power outage.
posted by Mitheral at 6:42 PM on May 12

"... I couldn't find specs for a 5 cu.ft. but for example the Fridgidaire 13 cu.ft. auto defrost[PDF] has a 130W heating element. And FYI the light bulb in a freezer only operates when the door is open. A defrost heater can run for as much as 20 minutes out of every 8 hours. The model above runs it's heater for 30 minutes for every 12 hours of compressor run time. ..."
posted by Mitheral at 9:42 PM on May 12

Actually, almost none of that is true, from your own example.

The spec sheet in your link says, specifically: "An automatic 30 minute defrost period is initiated after every 12 hours of compressor operation. During the defrost period a thermostat will switch the defrost heater off after the frost on the evaporator has melted. The defrost thermostat closes at 10° F and opens at 50° F." The heater specifically doesn't stay on for the whole 30 minutes. It is cycled, under thermostatic control, to only generate enough warmth to melt the frost on the condenser plate, and never gets above 50° F. It doesn't run the whole 30 minute defrost period, nor even, usually, much of it. Even the circulator fan in most modern units is cut off after 5 minutes, if there's no more frost accumulation. Not likely the defrost cycle is going to "cook" much, any more than a glass of tap water will.

The performance figures from the table below that paragraph, which is where I guess you're getting your idea of the electrical rating for the defrost heater element, are, in fact, for the whole freezer's operation, specifically measured during the last 1/3 of the compressor cycle (when the compressor is pumped up fully). The compressor motor's draw at 90° F ambient in that example is 115 to 130 watts. There's no mention of the power draw of the defrost heater, in that .pdf file. If we checked the service manual, I bet it would be less than 25 watts.

So, as far as it goes, your example validates my description of frost free operation, not your idea of it.

As for your freezer burn concern, geez, I haven't seen any food "freezer burned" in any of the last 2 or 3 refrigerator or freezers I've owned (that goes back 20 years or more). I freeze in freezer bags or freezer wrap, generally, and occasionally, in plastic tubs. Most commercially frozen foods, which I use regularly, licked the freezer burn problem with their packaging by 1990.

I do notice that my frost free units hardly ever have odor issues, because the dry, cold environment doesn't support mold or bacteria. I still sanitize my freezer sections once a week, just by moving things around, and wiping with sanitizing solution, but that's more force of habit, and the fact that my brother spills stuff, than real need.
posted by paulsc at 7:50 PM on May 12

Southern California Edison seems pretty reliable, but if you are -very- concerned about power cuts then perhaps you would want to look at a gas freezer. These are from my POV insanely expensive. I have a Servel refrigerator/freezer that runs on gas and electricity (you have to change over the source of energy manually). It has been stone reliable in 100 degree heat. I use propane as a fuel but as you see these can be converted to natural gas.
posted by jet_silver at 9:35 PM on May 12

I've got the Frigidaire FFC0723D 7-cubic foot. It seems to do the job, no big spike in power consumption either.
posted by electroboy at 7:36 AM on May 13

electroboy, where did you buy it? I'm in the market for one myself. CR says it goes for $250. A few places online have it for less, but the shipping costs always make it much more.
posted by Kirth Gerson at 10:56 AM on May 13