Consider the significant amount of money you’ve invested in the food stored in your deep chest freezer or fridge /refrigerator freezer. The last thing you want is for it to spoil during a prolonged power outage, leading to a substantial financial loss. To prevent this, let’s delve into two key aspects: how long it takes to run a generator for a freezer (or refrigerator) during a power outage and what size generator to use.
A freezer or refrigerator will stay colder longer if it’s relatively full during a power outage. The fuller it is, the more cold “mass” inside. The more mass, the longer it will stay cold. This is a critical concept to understand. Knowing your chest freezer is full will ensure that it remains frozen longer than if it is only partially filled.
Depending on the freezer, most fairly full chest freezers will likely stay frozen for approximately 24 to 48 hours. Your mileage may vary… I would be concerned after 24 hours without power.
A freezer part of a refrigerator won’t stay frozen as long as a chest freezer. They’re smaller and usually less insulated, too.
First, I recommend the battery-powered ‘portable power station’ concept, also called a ‘solar generator’ (although it can be recharged in other ways, too). It’s safe for use indoors, silent, and incredibly convenient. Several popular brands dominate the market and come in varying energy capacities depending on your needs. The Jackery brand is the most popular. Ecoflow is also quite popular, along with others. Take a look at which battery generator I use below…
You do not need a big generator; it does not have to run full time to keep your freezer or fridge cold during a power outage (save fuel!). Here’s what to know and what to do.
The power consumption of a chest freezer or refrigerator is not a lot (read caveat below). Here’s how it works:
A freezer or refrigerator has a compressor that makes it cold. The compressor is not always on; instead, it runs in cycles, triggered by a thermostat inside the freezer.
This compressor may require approximately 80-150 running watts. Note that there is a very brief startup surge, which may be up to 3-5 times higher. I measured how many running watts each of my chest freezers use when cycled ON:
- Danby 7-cubic-foot chest freezer draws 80 watts.
- GE 10.6-cubic-foot chest freezer draws 125 watts.
- GE 15.7-cubic-foot chest freezer draws 125 watts.
Caveat: When the compressor first 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 inrush current may be ~5x (or more) of the standard running power.
So, depending on the specific freezer, this might equate to approximately 600 to 1,200 watts for generator loading.
One of my portable gas generators is a small 2,000-watt Yamaha/Inverter, and it WILL run a chest freezer, even with the startup watts, no problem. I also have an Ecoflow DELTA 2 Max ‘battery generator’ which can run all three of my chest freezers, no problem.
(I LOVE my Ecoflow!)
First, you don’t need to run a gas generator constantly. That’s a waste of fuel. I analyzed the power consumption of my three chest freezers and discovered that, on average, the compressor is only ON about 38% of the time in my house. Call it 60% OFF and 40% ON for 24 hours.
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 the temperature inside the fridge or freezer (see below).
I can tell you what I recommend, and what I do…
Typically, a chest freezer may be around 0 degrees F or thereabouts. During a long-term power outage, as the internal temperature climbs into the teens, I would start powering it with a generator.
Most chest freezers are recommended for operating and freezing foods to zero degrees F or below. However, during a power outage, it’s okay if the temperature rises higher (as long as it stays below 32F).
Remember, less energy is required to maintain a cold/frozen freezer temperature than to bring it down from a warmer temperature.
If I were you, I wouldn’t wait until it crept up towards 32 degrees. Instead, I would begin operating my portable generator to provide power to my chest freezers after ~ half a day. I would run it for about an hour several times during 24 hours, running it more (or less) based on the internal temperature (see below).
Monitor the internal freezer temperature and keep up with it. Your times will vary.
A while back someone asked about running fridge and freezer with a generator… My power outages from storms in Tennessee (which a couple lasted over two weeks) helped establish required generator run times for both appliances.
I soon realized that keeping both the fridge and freezer full helped maintain the correct temperatures for both, with food or bottled water and liquids.
My minimum run times that maintained temps was 30 minutes every 15 hours, depending on how well your appliances are insulated.
Use a dedicated thermometer inside both to verify safe temps, which takes the guesswork out of the equation.
Some preppers have made the mistake of running a generator continuously during an outage. Don’t make that error.
~ Realist
Here’s what I use to monitor my refrigerator/freezer temperature. It would be perfect during a long-term power outage, too… There’s a temperature display unit that magnetically sticks to the fridge. And two temperature sensors that can clip somewhere inside (and there’s a suction cup).
(AcuRite on Amazon)
When using a portable gas generator, always operate it outdoors (not in your garage!).. Use a high-quality, proper-gauge extension cord to bring power into the home (e.g., through a window).
[ Read: Best Extension Cord for your Generator ]Keep a wirelessor wired thermometer inside your chest freezers so that you can read the temperature without opening the freezer during a power outage!
And I always use this method to watch my deep chest freezers!
(Ambient on Amazon)
I purchased the unit linked above. It comes with three wireless sensors, which go inside the freezer. This may work well for you. Use lithium batteries (they perform much better in the cold!).
However, you can also get sensors with an attached probe that is placed in the freezer while the transmitter is outside the freezer (photos below). These sensors will work fine with the WS-10 base unit above.
I have one in each of my chest freezers. There’s also a temperature readout panel mounted on the wall right above the freezers, so I always know what the temperature is inside. The internal temperature is also transmitted wirelessly to a readout panel, which I keep on the window sill above the kitchen sink.
As you can see in the image below, I am monitoring three freezers. The display also shows the room temperature.
This next photo shows the temperature probe inside the chest freezer. I used a piece of tape to hold the wire, as shown. I like this type of freezer thermometer sensor: The transmitter is outside the freezer, so it works better (it has a more extended range because the freezer’s shell less hinders the signal). And the battery isn’t in the cold.
How To Measure Power Consumption of Appliances
How To Know Your Freezer Thawed While You Were Away
2 Reasons Why Lithium AA Batteries Are Better Than Alkaline
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