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If you are planning backup power for a freezer, the type you own changes the battery you need. According to ENERGY STAR, a certified chest freezer uses about 215 kWh a year while a certified upright freezer uses about 395 kWh a year. Averaged over the year, that is roughly 25W for the chest and 45W for the upright, so the upright needs close to twice the battery for the same outage.

How the numbers work: wattages are typical ranges from manufacturer spec sheets and efficiency labels, so check the label on your own appliance. Runtimes are calculated, not lab-tested: usable energy = rated Wh × 0.85, divided by average watts.

⚡ Quick Answer

• Chest freezer: about 215 kWh/year (ENERGY STAR certified), which is about 0.59 kWh per day, or roughly 25W averaged over the day.
• Upright freezer: about 395 kWh/year (ENERGY STAR certified), which is about 1.08 kWh per day, or roughly 45W averaged over the day.
• Why the difference: ENERGY STAR says chest freezers are typically more energy efficient because the top-opening door lets less cold air escape.
• For an outage: the chest freezer is usually the cheaper one to keep running. The upright is easier to organize, but you should plan a bigger battery for it.
• Older or garage-kept units use more. The numbers above are for certified models. An older freezer, or one in a hot garage, can use noticeably more, so check the EnergyGuide label on yours.

📊 Side by Side

	Chest freezer	Upright freezer
ENERGY STAR certified annual use	about 215 kWh	about 395 kWh
Estimated yearly running cost (ENERGY STAR)	about $30	about $60
Average draw (annual kWh / 8,760 h)	about 25W	about 45W
Daily energy	about 0.59 kWh	about 1.08 kWh
Door	Opens from the top	Front door, shelves

The running cost and annual kWh figures come from ENERGY STAR’s freezer page. The average-watt and daily-energy rows are our own arithmetic from those numbers.

🔋 How Long Will a Battery Run Each One?

Calculated runtimes, using usable capacity of 85% of rated watt-hours. The first two rows are the ENERGY STAR averages. The last two add a cushion for an older unit or a hot garage (roughly 1.5 to 1.6 times the certified average).

Freezer and average draw	EcoFlow DELTA 3 Plus	Jackery Explorer 1000 V2	Bluetti Elite 200 V2	EcoFlow DELTA Pro	Bluetti EB3A
Chest, certified average (25W)	34.8 h	36.4 h	2.9 days	5.1 days	9.1 h
Chest, older or hot garage (40W)	21.8 h	22.7 h	44.1 h	3.2 days	5.7 h
Upright, certified average (45W)	19.3 h	20.2 h	39.2 h	2.8 days	5.1 h
Upright, older or hot garage (70W)	12.4 h	13.0 h	25.2 h	43.7 h	3.3 h

What this means: a 1,000Wh-class battery can carry a certified chest freezer for around a day and a half, while the same battery carries a certified upright for about 19 to 20 hours. With solar panels, either can be refilled during the day. For more detail on chest freezers specifically, see how many watts a chest freezer uses.

🔌 Surge Matters More Than Watt-Hours

A freezer’s compressor needs a short spike of power to start. That spike is set by the LRA (locked rotor amps) on the freezer’s data plate, multiplied by 120 volts. A battery can have plenty of watt-hours and still shut off at startup if its surge rating is too low. We explain how to find and use that number in what LRA means on a freezer and in surge vs running watts.

🥶 Keeping Food Safe

• Keep the door closed. The USDA says a full freezer holds its temperature for about 48 hours, and a half-full freezer for about 24 hours, if the door stays shut.
• Fuller is better. The USDA figures above show it: a full freezer holds about 48 hours, a half-full one about 24.
• Use an appliance thermometer so you know what temperature the food has actually been at. Our food timeline covers what to keep and what to throw away.
• Do not run a generator in a garage or enclosed space. If your freezer lives in the garage, the CDC says generators must be used outdoors, well away from windows, doors and vents, because of carbon monoxide.

✅ Which Should You Back Up?

If you already own one, back up the one you own and use the calculated runtimes above. If you are choosing between them partly for outage planning, ENERGY STAR’s numbers favor the chest freezer: it takes roughly half the energy to run, so a smaller battery covers it for longer. If you prefer an upright for organization, size the battery for about 45W average and a little more for an older model.

For full buying advice, see best solar generator for a chest freezer and the chest freezer blackout math.

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🔗 Related Guides

• How many watts does a chest freezer use?
• What is LRA on a freezer?
• Best solar generator for a chest freezer
• Chest freezer blackout math
• How long does food last without power?
• Surge watts vs running watts

❓ Frequently Asked Questions

Does an upright freezer use more electricity than a chest freezer?

According to ENERGY STAR, a certified upright freezer uses about 395 kWh a year, while a certified chest freezer uses about 215 kWh a year. ENERGY STAR says chest freezers are typically more energy efficient because the top-opening door lets less cold air escape.

How many watts does an upright freezer use?

A certified upright freezer averages about 45W over a year (395 kWh divided by 8,760 hours), which is about 1.08 kWh per day. It draws more while the compressor is running and less when it is idle, and an older unit can use more.

How long will a 1,000Wh battery run an upright freezer?

At a 45W average and 85% usable capacity, a 1,000Wh battery runs a certified upright freezer for roughly 19 hours. A 1,024Wh unit gives about 19 hours and a 2,073.6Wh unit about 39 hours. Surge rating also has to cover the compressor’s startup.

How long does food stay frozen in a power outage?

The USDA says a full freezer keeps food safe for about 48 hours, and a half-full freezer for about 24 hours, if the door stays closed.

Is it safe to run a generator near my freezer in the garage?

Not inside the garage. The CDC says to keep generators outdoors and well away from windows, doors and vents, because they produce carbon monoxide. A battery power station does not produce exhaust, but a gas generator does.