Your chest freezer (or two), or even your fridge /refrigerator freezer may have LOTS of $$ money worth of valuable food inside. The LAST thing you want is for it to spoil during a longer lasting power outage that lasts more than just a few hours!
Here are a few pointers how to best deal with this situation. And a few recommended items to have on hand which will greatly help in the process.
Much of this is common sense. But it’s important.
A freezer or refrigerator will stay colder, longer, if it’s full during a power outage. The fuller it is, the more cold “mass” inside. The more mass, the longer it will stay cold. It’s simply an important concept to understand. If you know your chest freezer is full, it’s definitely going to stay frozen for a lot longer.
In my estimation, most chest freezers that are fairly full will likely stay frozen for… lets say ~ 24-48 hours. (For those who have direct experience with this unfortunate long-term power outage vs. chest freezer or fridge scenario, lets hear your story in the comments below!)
The freezer within a refrigerator probably won’t stay frozen as long compared with a chest freezer. They’re smaller. Probably less insulated too.
The first suggestion, thick, heavy, blankets! Drape blankets over the chest freezer. It’s additional insulation. Just be aware if there are any slotted vents (don’t block them), because we’re going to intermittently power it up with a generator. Read on…
Size of Generator To Run A Chest Freezer or Refrigerator
You do not need to run a generator full time to keep your freezer or fridge cold during a power outage! Save fuel. Here’s what to know and what to do…
There’s no need for a “Super Max Turbocharged Fuel Injected 500-Horsepower Big Block” generator to get the job done! The power consumption of a chest freezer or refrigerator is not huge. Here’s how it works:
Freezers work like refrigerators, by compressing air or fluid into a small space and then letting that air or fluid expand into another space.
(the science behind it)
Compressing the fluid makes it give off heat, which happens in the back of the freezer. Letting it expand causes it to draw in heat, which happens inside the refrigerated box.
They run in cycles, triggered by a thermostat inside the freezer.power cycles on and off.
The energy used while it’s cycled “ON” will likely be in the vicinity of ~150 watts. I recommend that you do what I have done, and easily measure it yourself. Here’s an article on how to do it, “How To Measure Power Consumption of Appliances” .
Caveat: When the compressor fist turns on, there is a higher power consumption (inrush surge current, or, “starting watts”). It begins high for a fraction of a second and reduces to “running watts” after a very short time (seconds or less). This may be ~5x (or more) of normal running power. So, for generator loading, this might be 600 to 1,200 watts, depending.
One of my portable generators is a small 1,000 watt, and it WILL run a chest freezer, even with the startup watts.
I would say a 2,000 watt or higher will be just fine.
How Long To Run Generator For Chest Freezer or Refrigerator During Power Outage
First, you don’t need to run it all the time.
There’s not a clear answer. It will depend on how much cold mass (food) is inside, how well it’s designed and insulated, the ambient temperature of the environment, and whether (or how often) you’ve opened it up to have a look inside.
I can tell you what I recommend, and what I do…
Monitor Freezer Temperature With Wireless or Wired Thermometer
Keep a wireless, or wired, thermometer inside your chest freezers so that you can read the temperature without opening it up during a power outage! This is extremely helpful during a longer term power outage. And it’s just good to keep an eye on otherwise!
I have one in each of my two chest freezers. The readout panel is mounted on the wall right above them. I always know what the temperature is inside. They don’t make my model sensor anymore, but the equivalents can be seen here from amzn:
Wireless Freezer / Refrigerator Thermometer
Wired Freezer / Refrigerator Thermometer
Worst, case, as the internal temperature begins to approach 32 degrees F, time to run the generator. But I wouldn’t wait that long.
Most chest freezers are recommended to operate and freeze foods to zero degrees F or below. I generally set mine to about -10F. When it’s that cold, foods will store even longer. However, during a power outage it’s okay if it comes up higher (as long as it stays below 32F).
Remember, Less energy is required to maintain a given (already cold) freezer temperature than it does to bring it down from a warmer temperature.
If it were me, I wouldn’t even wait until it creeps up towards 32 degrees. Rather, I would begin operating my portable generator to provide power to my chest freezers after ~ half a day has gone by. I would run it for about an hour, several times during a 24hr period for starters…
Simply monitor the internal freezer temperature change and just keep up with it. Your times will vary.
Safety Considerations with Generator
When using a portable generator, always operate it outdoors (not in your garage!). Use high quality and proper gauge extension cord to bring power into the home (e.g. through a window).
Continue reading: Best Extension Cord for your Generator
Great article, but I would like to see someone do one of these articles advising the differences of at least three climates, hot, mild or cool, and cold. “Best practices” differ in the different climates. I realize that it makes a difference in all climates as to whether the outage happens in the summer or in the winter, but still, things will be different for both seasons in different climates.
FWIW- No generator here.
CD in Oklahoma
CD,
That’s where a bit of common sense comes in. The hotter the environment the quicker the freezer will warm up. All chest freezers and refrigerators have built-in insulation, which will dampen the effects of external temperatures to an extent. The variations in thermal characteristics are somewhat minimal in the context of overall longer term power outage mitigation (generator, alt-energy) vs. losing the food contained within after a day or two or three…
I wonder if there are any experiments with freezer performance in hot vs cold situations. I see freezers in garages in the hot summer sun, sure insulation is doing it’s job but there are limits. The coils are going to have a harder time transferring heat to the room temperature if it is 90d instead of 65d which adds even more heat to the room.
I’ve often thought refrigerators and freezers should have the compressor away from the unit, in a basement even, and keep the heat out of the room, which would also make more room in refrigerator for food.
Don’t forget the coin in a glass of ice trick!
And what is that😉
Our Standard procedure when expecting a hurricane in say 48 hours is to put containers of water in any empty space in the freezer. Then turn the thermostat to the coldest setting. After the power goes off then cover with blankets. Running the freezers and refrigerator on a generator at least one hour each day without power AFTER removing the blankets has worked for many years and many hurricanes. Running one hour every twelve is better if you have the fuel but one hour a day will get you by. Leave the thermostat on max cold until power is restored works best. The freezer will run during that hour until it shuts off usually before the hour is up.
Great advice. Thanks.
Deep South, thank you for sharing your methodology. We’re going to put 1-gallon jugs in the freezer and start that ‘habit’ now that we’ve learned this tip.
When we’ve had long outages, we hook up our genny, but never used it as infrequently as you suggest. We’ll be more frugal next time, and since we’re not deep in the south, we’ll probably have less chance of melting than you surely experience.
Thanks!
That is the best info I have heard. I too, am from the deep South and have lost food because of not having a generator and not knowing that covering the freezer with blankets could prolong your chances of not losing food. Now, the season is here again for hurricanes and tornadoes. I’m ready :)
If there is empty space in the freezer I fill it with 1 gallon milk jugs filled with potable water. As Ken mentioned this helps to keep things colder longer. It also gives us water for use if we have a long term situation.
We did have a 3 day power outage some time ago . We had 2 freezers that we kept frozen with our coleman 2200 watt generator and did not lose any food. This happened in the fall with a little cooler weather.
Bluesman, thank you for sharing this tip! I have some space on one shelf in our upright freezer. I also have spare 1-gallon plastic jugs I’ve been saving….guess what I’m doing tomorrow?!
This article is so helpful, and it’s comments like yours that teach me one more thing about household preparedness. Thanks so much.
You are welcome , glad I could help.
– We had a power outage of about a week, during the summer, in hot, dry, windy west Texas. We have two upright freezers (DW is short and does not like to fight with chest type freezers) We also have the house wired so that I can easily power both freezers and our side-by-side refrigerator, along with a couple of outlets and a light in the kitchen with my 7.5 kw portable genset.
Actually, before I got home, my son had hooked his 3.5 kw genset that rides in his work truck and was powering the house for about 12 hours before I got mine out and hooked up. (son didn’t know where mine was stored), To save gas and keep power available, we ran mine for an hour at a time, four times a day. This kept the blanketed freezers cold and the closed refrigerator at a usable temperature for a week.
The light in the kitchen was kept powered by my two x 105 amp/hour marine battery bank and a 400-watt inverter and recharged by the generator when we ran it. Since I’m not sure how much gas my son used with his, (He wouldn’t tell me after I offered to replace it) I’m guessing about 2.5 – 3 gallons there. We used six gallons for the rest of the week for my machine.
– Papa S.
– In our case, the four times daily were chosen to provide power at mealtimes to allow opening the refrigerator and freezer without worrying about cold loss. One of the outlets powered a 1200-watt microwave, so that was usable as well if desired. This was more for DW’s convenience and only secondarily to ensure that everything stayed cold. Just for those who are asking about the required frequency for running the genset.
– Papa
Good stuff
Most refrigerator freezers on the market are frost-free/auto-defrost models. Same with chest and upright freezers. That means that periodically throughout the day the appliance will enter a warm cycle to melt any frost inside.
The frequency of the warming cycle, the length of the cycle, and the amount of temperature rise (sometimes well in excess of freezing), varies by model.
Ken – do you have any data on how running a freezer for an hour or two a day will affect this warming cycle? If the goal is to keep frozen stuff frozen, might be good to know.
For those with manual defrost, ice and frost are insulators and the thicker it is the harder your compressor has to work to cool down the inside.
I have 3 chest freezers/did have 4 till sold one.–neither is auto-defrost.
My chest freezers are not auto-defrost.
However that’s a good point if someone does have one, because it would be sort of a wast to be running the generator during ‘defrost mode’. I have not investigated how long that cycle is, or if there’s a way to even know it’s on that cycle… food-for-thought
I was just shopping for a chest freezer and I found that most chest freezer are not frost free. I know that my fridge freezer is, but my upright freezer is not…probably wouldn’t be a concern for most people…
In April of 2011 when devastating tornadoes blew through the southeast we were without power for the longest I had experienced, 7 days. I was not really prepped but had some basic habits that worked to my advantage. I had always kept 10-15 gallons of gasoline around and at the time had three vehicles full of fuel.I did not own a generator but did own an 800w continuous output inverter which I Hardwired with 12ga romex to my wifes Nissan Altima battery. The car was moved out of the garage. The inverter would not pull the freezer and fridge simultaneously so we alternated every two hours and would would leave them both off for extended periods at night. The vehicle fuel managed to get us through. I now own a 6000 watt generator, an inverter 1000w (which will pull both units), and keep extra fuel around.
We lost no food to spoilage.
We cooked pancakes, made coffee and all other cooking on a gas grill.
Thanks for the report, and tips! Good one, regarding the inverter to running-vehicle.
Excellent piece of information from an actual experience; 7 days without power in the south running a freezer off an inverter on the auto battery. I’ve got a 1000w, it is time to experiment!
This may be a dumb question, but if you have a generator (mine has 120 volt outlets), what is the inverter used for?
Mike
Mike:
An inverter based generator uses solid-state components to create the AC current in a more perfect sinusoidal waveform. Non-inverter type generators approximate the waveform, in a less-than perfect state. On a scope most portable generators output waveform is ragged, with saw-tooth texture to it; and it decays with increasing loads. Inverters hold their output quality across the powerband.
Which appliances would benefit from the inverter generated current vs the generator?
If you are putting frozen water bottles in the freezer, I always put them at the top since that is where most of the defrost occurs(my experience). On an upright, run a couple courses of visquine/seran wrap top to bottom inside the refrigerator/freezer and leave a slit in the middle to get stuff out; it does seem to help when you have open the doors to get stuff out.
Ken, few years back, our vicinity had a huge power outage. My nephew took his generator and went around to family members whose power was out and ran their freezers for an hour or so. Once the compressor was ran couple times, he would go to the next. This worked great.
That’s a good example how you don’t need a large heavy generator to get the job done. A small portable generator that you can easily transport is nice to have.
Ken,
I know that a generator is a big investment for preppers on a tight budget, but most of us believe in redundancy. Good idea to have the goal of two generators. The old “two is one, one is none” rule.
I have two. One is a 13.5KW, the other is a 4KW. I also store a 8KW for a friend. Been thinking about buying one of the cheaper 2KW as backup to the backup.
Dennis,
I agree with 1 is none, 2 is one and I like to take it one more step…3 is BETTER!
Good on you with the level of preparedness situation with generators!
I’ve been shopping whole house generators for a while and hope to soon make my purchase and get it installed.
Slippy==== is a whole house generator kept/run outside, or is there such a model which can be kept/run inside? Roughly how much is the cost? thks
Slippy and others
Depending on the power usage in your whole house, it might be much cheaper to install a transfer switch that only energizes about eight of the most important circuits in your house. You may be able to go from a 13kw generator down to a 6kw unit – much cheaper to buy and to run. Try for a generator that runs at 1800 rpm rather than the most common 3600 – much quieter and better fuel economy.
On a related note, I installed a similar generator transfer switch for my dad a number of years ago. It powers up select (most important) circuits in the house during a power outage. That way you don’t need a “whole house” generator. We utilized this one: Reliance Controls 6-circuit transfer switch
Good point hermit us. Something else I did was.
I got 3 inch red letters and put them on the cabin breaker panel, transfer switch, and the breaker switch next to the power meter.
Clearly marked A B & C. I wanted to make it as simple as possible for anyone, including my grandkids, to be able to do what’s necessary during a power outage.
Inside each panel or breaker box. I made step by step labels on what to do to go to Generator power. Also color coded some of the instructions with red labels to remind anyone that they need to make sure every step was followed.
Its a no brainer process for me and you. But not for everyone. You or I might not be around when the power goes out. I tested the ABC 123 labeling set up on my wife and 8 year old grand daughter. They can get er going in less than 5 minutes.
The best thing is we are wired for ac grid power, generator power, and have solar lights and outlets in all rooms.
We lose power often. And unless there’s a major outage that will last for a long period. We just use solar.
Jane Foxe
I use the term “whole house” generator but the more appropriate term is “stand by” generator.
This type of generator is usually placed outside the home and LP Gas, Natural Gas, Diesel or Gasoline can be used to power it. LP gas is the option that I will use as I have a large LP gas tank already on my property. No access to Natural Gas. Diesel would be another option but I’d never think about gasoline due to ethanol negative affects on small engines.
I have not run across any that you would want to set up to run inside your home.
My strategy is to use it to run necessary and essential circuits. So to size your Stand By Generator, determine what circuits are essential then figure out the wattage to run them. For example if your coffee maker, jacuzzi and juicer are essential, (HA) determine the watts needed and you can then settle on an appropriate sized generator.
Seriously, we plan on running refrigerators/freezers, about 4-5 outlets, 2 ceiling fans and a furnace fan. I’d never consider to attempt to run the whole house (especially AC) as the KW’s needed would make the generator way out of my price range.
Expect to pay anywhere from $2000 for a 7.5KW Generator, around $3000-$4000 for a 10KW-12KW unit and obviously the sky is the limit if you wanted to shell out $30 Grand for a 150KW monster go for it! (prices are “on average” and will vary based upon your specific situation).
Hope this helps!
Slippy– Thank you. Nice explanation(s). Did not think one could run this “in house”, but wondered if there was something “new”.
Our upright freezer is an old model that does not have self-defrost. I’ll never buy one that is. I’m not sure about our upright side-by-side refrigerator/freezer. We get them from a local used-appliance dealer that buys surplus from area military bases (they remodel from time to time just for the hell of it). The side-by-side doesn’t have anything very valuable in it, especially the freezer (ice cream, frozen water in milk jugs for out-of-town purchases, spices, mixes, etc.).
We bought our upright freezer new back in the early 80s and although it may be on its last legs, it’s still working like a champ. We defrost it once a year. We’ve always lived rural with plenty of power outages, and we learned early on to leave the plug out of the drain hole, and be sure to route the drain hose out to the front of the freezer. A small trickle of water on the kitchen floor in front of the freezer is an indication that the freezer has thawed a bit. Usually, upon inspection, we found that the freezer thawed enough to begin a trickle in the drain pipe, and then the power came back on to stop the thawing. A large puddle on the floor would be something else that would require deep investigation and possible voluntary destruction of all foods within. We haven’t had that happen in 44 years together. That’s why we can’t justify buying a generator and fuel storage to power it.
My wife put a bunch of plastic baskets in to help divide the foods into groups. I partially filled ziplock bags with water and stuffed them into the small spaces between baskets where we couldn’t put any food. Along with the milk jugs, cottage cheese containers, and sour cream containers filled with water, the freezer space is fairly well occupied. If space is needed for food, some of those containers get taken out and discarded.
We went through a 5-day outage (without generator) in December 2015 (ice storm), and the freezer held just fine. We never opened it, and the ambient temperature in our kitchen was a few degrees above and below 35 degrees during a 24-hour day (we don’t heat our kitchen when we have no power). We pitched out a few things from the S-B-S freezer (prepared foods) and had all of the perishable things out of the refrigerator in coolers on the back patio cooled with ice from our rain-collection tubs. To pass the time, we cut downed trees on our fence in the backyard, played lots of Cribbage games, sewed on a treadle sewing machine, cracked a bunch of pecans that I hadn’t seemed to find time before a 5-day outage, and kept a very close eye on that freezer drain hose. Life goes on.
CD in Oklahoma
My small chest freezer is not a self defrost model. I use the cloth grocery bags to put stuff in. I staple a tag on the strap as to what is in the bag and have made some attempt to color code them- red/meat- green/bacon, sausage …..
We do the same with cloth grocery bags, except our color code is brown-beef, pink-pork, blue-fish, yellow-chicken, whatever works for you!
you have a better color selection than I do -I just might have to go buy a couple of different colors. : )
We once went six days without electricity in December in North Missouri during an ice storm. First thing we did once we pulled out the generator was wire up the furnace – we did this using an extension cord that we cut one end off of and store in a handy place just for this purpose. The furnace cycled like it did when the electricity was on. We have a gas water heater with a pilot – always had hot water and hot showers all six days. I rotated another extension cord between the freezer and the fridge allowing them to cycle – once they went off I switched to something else. In between I was able to run the dishwasher, the microwave, even ran the vacuum cleaner one afternoon, and during the evening we were able to run the TV, (several years ago) VCR, and a light or two along with the furnace. I did do a load of laundry and hung clothes in the basement to dry as well. I spent a lot of time rotating the cord from this to that. We have a small generator, not some huge thing. We weren’t expecting to be without electricity although we’d stocked up on milk and bread, etc. before the storm, and certainly weren’t expecting to be out that long. In fact, the first night, we just piled on blankets thinking it would be on by morning.
At No Tech Magazine’s webpage I found an interesting version of the “Add Gallon Jugs of water to freezer IF your expecting a power outage”.
Some smart soul created a Solar Powered Chest Freezer that don’t use batteries as batteries are expensive and short lived. Instead he uses a large mass of water inside the freezer. Now that takes room up in the freezer and I am wondering if steel plates might give you better Cold Mass Storage than water….
Also in the keeping food cool department a friend of mine plumbed his well water THROUGH the side of his Refrigerator in an attempt to use some of that cold water to cool it. Using the watt miser over a months use it did indeed chop his power use almost 50% but then again New England Well water is pretty darn cold. Folks used to lower food in a basket into dug wells for the cooling benefit.
I understand that the article is about preserving your frozen goods with a generator, but for those of us who either do not have a generator, or the darn thing will not start, or no fuel, if possible try to purchase some dry ice.
americuh
I would deliver beef to my siblings with dry ice in large ice chests. If you do use it, wear gloves to protect your hands. Keep the dry ice wrapped in news paper it will hold longer. Know that it will only hold for so long that way, that will depend on the weather you are dealing with at the time of power loss.
We were delivering beef to my brother from CA to WA, and we had to replenish the dry ice since we stayed over in Oregon to visit family. That was in April, a warmer spring that year so the need for the extra dry ice. FYI
Putting wet towels or blankets on top of a refrigerator or freezer helps too as heat is drawn off from the appliance as the water evaporates. Probably won’t work well in humid environments , but works good in more dry ones in conjunction with any of the other tips posted.
Great information-thank you for the site! Are there any issue/problems with the freezer’s compressor or other parts/components failing due to the periodic power on/off caused by the use of a generator?
It is my general understanding that if unplugging (powering down) a fridge/freezer while the compressor is running, it’s best to wait a little while before powering up again. How long is a little while? 10 minutes? Maybe someone who knows more about refrigeration / compressors can input their knowledge.
Ken…only saying this from what I was told from repair persons….
was told to not unplug while the compressor was running…Wait till it stops.
Jane:
Let me just add, never have an inductive load, such as a motor/compressor, plugged-in to a portable generator, when starting the generator. Always get the engine/output stabilized before connecting a load.
To the time-out for a compressor, most are capacitor start; that system needs a few seconds to recharge. Further it seems advantageous to let refrigerant pressures in modern AC/Fridges equalize before starting the compressor. There may also be some minor concern about thermal expansion in tight tolerance areas. Perhaps an HVAC professional can give better info.
tmcgyver – good info. Thanks
How would solar generators / battery work on 8 cub ft freeze or not.