Quick answer: 0.55 to 0.95 kWh a day, from 9 to 21.7 cubic feet. That makes chest freezer watts an average of 23 to 39, not the 300 to 700 W commonly quoted. And for the first 48 hours of an outage a full one needs no power at all.
This is one of the few questions on this site with an exact answer, because every freezer sold in the US carries a certified annual consumption figure. Divide by 365 and you are done. No estimating, no power factor, no duty cycle.
Our appliance wattage chart deliberately leaves the chest freezer row blank, because only nine models hold current certification and nine is too few to publish a percentile range. Nine is plenty to publish as a list, though, so here they are.
Chest freezer watts for every model with current certification
This is not a sample. It is the complete list of chest freezers holding ENERGY STAR certification when we queried the database, with three omitted only because they are relabelled versions of models already listed, carrying identical capacity and identical certified consumption.
| Model | Capacity | kWh/year | kWh/day | Average watts | Cost/month US | Cost/month UK |
|---|---|---|---|---|---|---|
| Whirlpool WZC3209LW | 9.0 cu ft | 201 | 0.55 | 23 | $3.07 | £4.37 |
| Danby DCF100A5WDB | 10.0 cu ft | 211 | 0.58 | 24 | $3.22 | £4.59 |
| Frigidaire EFRF1005 | 10.1 cu ft | 213 | 0.58 | 24 | $3.26 | £4.63 |
| GE FCM11PH | 10.6 cu ft | 218 | 0.60 | 25 | $3.33 | £4.74 |
| GE FCM16DL | 15.7 cu ft | 277 | 0.76 | 32 | $4.23 | £6.03 |
| GE FCM22DL | 21.7 cu ft | 346 | 0.95 | 39 | $5.29 | £7.53 |
Notice how flat that is. Going from 9 to 21.7 cubic feet is 141 percent more space for 72 percent more electricity. Per cubic foot the largest freezer here is about 29 percent more efficient than the smallest, which is the opposite of what most people assume when they buy the small one to save money.
What if mine is not on the list?
Most chest freezers are not certified, and that is fine, because federal law caps them anyway. ENERGY STAR publishes the applicable federal maximum next to each model, and fitting a line through those figures reproduces the Department of Energy’s standard for manual-defrost chest freezers almost exactly: about 7.3 kWh per year for each cubic foot of adjusted volume, plus 108.
So the worst chest freezer the law permits at 21.7 cubic feet uses 1.06 kWh a day against the certified 0.95. The certification is worth having, but it is not the difference between a cheap freezer and an expensive one to run. A freezer that predates the current standard, or one kept in an unheated garage in summer, will do worse than either figure.
Chest freezer watts per day is the wrong unit, and the right one
Search results for this question routinely answer “300 to 700 watts”. That is not wrong so much as answering a different question: it is roughly what the compressor pulls while it is actually running, and a chest freezer’s compressor is off most of the time.
Spread across the day, a certified chest freezer averages 23 to 39 W. That is between seven and thirty times less than the figure usually quoted. For sizing a battery, the average is what matters, because you are buying kilowatt-hours.
We are not going to publish an instantaneous compressor figure, because no manufacturer of these nine models publishes one. If you need it for your own unit, it is on the rating plate inside the lid or on the back, and the same warning applies there as everywhere: amps times volts gives you a ceiling, not a draw.
The outage answer is usually: do nothing
This is the part that changes what you buy. USDA guidance on food during a power cut is specific: a full freezer holds a safe temperature for about 48 hours, and a half-full one for about 24, provided you keep the door shut. A refrigerator gives you four hours.
Most outages end well inside the 48 hours the USDA allows for a full freezer. So for the majority of them the correct action for a full chest freezer is to leave it closed and not connect it to anything at all. Opening it to check is the one thing that spends the reserve. What to do with the rest of the first hour of an outage is a separate list.
And if you do decide to run it, the arithmetic is almost embarrassing: two days of a 21.7 cubic foot freezer is 1.9 kWh, about 35 US cents. A modest portable power station covers that several times over. The freezer is not what makes an outage expensive; the well pump and the furnace blower are.
Two practical notes, both cheaper than any equipment in our appliance power section. A freezer that is half empty holds cold for half as long, so filling the space with containers of water buys you hours for nothing. And a chest freezer beats an upright here because cold air does not fall out when the lid is opened.
Food safety, not electrical safety. Judge frozen food by temperature, not by how long the power was off. The USDA rule is that food which still contains ice crystals, or is at 40 °F (4 °C) or below, may be safely refrozen, though quality may suffer. Anything warmer than 40 °F for more than two hours goes in the bin, and you never taste food to decide. A cheap freezer thermometer left inside removes the guesswork, and it is worth more than a generator for this particular problem.
If you do run a freezer from a generator, the generator goes outside, well away from windows, doors and vents. Carbon monoxide from a portable generator kills quickly and cannot be smelled. Never run one in a garage, even with the door open, which is exactly where chest freezers tend to live.
Frequently asked questions
How many kWh does a chest freezer use per day?
Between 0.55 and 0.95 kWh for certified models from 9 to 21.7 cubic feet. That is 201 to 346 kWh a year, or roughly $37 to $63 at the current US average price.
How long will a chest freezer stay frozen without power?
The USDA says about 48 hours if it is full and the lid stays shut, or about 24 hours if it is half full. Filling empty space with water containers extends that, and opening the lid shortens it.
Is a chest freezer cheaper to run than an upright?
Usually, yes, and it holds cold far longer in an outage because cold air does not spill out when you open the lid. Certified upright freezers cluster higher in the same database, with a median of 438 kWh a year against 201 to 346 for every certified chest freezer, though they are not matched for size.
Will a 1,000 W power station run a chest freezer?
Comfortably in energy terms: a full day is under 1 kWh. The question is the compressor starting surge, which the makers do not publish. Check the surge rating rather than the capacity, as with any compressor load.
Does a fuller freezer use less electricity?
The certified figures are measured under a standard test and do not vary with how you load it. What a full freezer definitely does is hold its temperature far longer once the power stops, which is the property that matters in an outage.
This article is general information, not an installation guide and not a substitute for a licensed electrician. Electrical work on a service panel, a transfer switch or a utility connection is regulated in most jurisdictions and normally requires a permit and an inspection. Fuel-burning equipment produces carbon monoxide and must never be run indoors, in a garage or near an opening into the home.
