How Many Watts Does It Take to Run a Freezer?
ENERGY STAR puts a certified chest freezer at about 215 kWh a year and an upright at about 395 kWh — roughly 25 and 45 watts averaged continuously. The compressor draws several times that while running and nothing while off, and its startup surge is the number that trips inverters. To size backup power you need your freezer's figures, not a category average.
Sources last checked 2026-08-31 · next review due 2026-09-30 · reviewed by HomesteadingGear Editorial
The three numbers, and why only one is on the label
| Number | What it is | What it decides |
|---|---|---|
| Running watts | Draw while the compressor turns | Continuous inverter rating |
| Surge watts | Spike as the motor starts, a fraction of a second | Whether the inverter trips. This is the figure people get wrong |
| Duty cycle | Share of each hour the compressor runs | Battery runtime and daily consumption. Never printed anywhere |
A nameplate tells you what the appliance can draw. It cannot tell you what it does draw, because that depends on how hard the compressor has to work in your room, how full the freezer is, and how often the door opens. That gap is why measuring beats looking up.
Chest versus upright
| Type | ENERGY STAR annual use | Average continuous draw |
|---|---|---|
| Certified chest freezer | about 215 kWh/year | about 25 W |
| Certified upright freezer | about 395 kWh/year | about 45 W |
Annual figures are ENERGY STAR's. The continuous-draw column is those figures divided by 8,760 hours and rounded — it is arithmetic on their number, not a separate measurement, and no real freezer draws a steady 25 watts. For scale, the EIA puts average US household use at about 10,500 kWh a year, so a chest freezer is roughly 2 percent of it.
Measure yours — it takes an afternoon
A plug-in watt meter costs less than a mistake in generator sizing. Plug the freezer through it and note three things:
- Running watts — the steady reading while the compressor is audibly running.
- Cumulative kWh over 24 hours — the meter's energy total. Divide by 24 for average watts, then divide that by your running watts to get the duty cycle.
- Surge — most cheap meters will not catch it. If yours does not, assume several times the running figure and size the inverter with headroom.
Do this in the season you actually care about. A freezer in an unheated garage in August behaves nothing like the same freezer in January, and outage planning usually cares about the harder case.
Runtime and inverter sizing
Average draw
48 W
1152 Wh per day
Estimated runtime
32.6 hours
On 1567 Wh usable
Inverter must exceed
600 W
Surge, not running
This is an estimate, and here is exactly why it is not a guarantee
- It assumes a steady duty cycle. Real compressors run more in a hot room, more after the door is opened, and more when the freezer is half empty.
- Inverter efficiency varies with load. A large inverter running a small freezer is less efficient than this single figure suggests.
- Battery capacity falls in the cold and falls with age. A nameplate figure is the best case on the first day.
- The surge figure is a floor. An inverter that merely matches the surge will trip; it needs headroom above it.
- Nothing here accounts for anything else you plug in at the same time.
Common mistakes
- Sizing to running watts. The inverter has to survive the surge. Matching the running figure produces a system that works perfectly until the compressor cycles.
- Using annual kWh as a live draw. 215 kWh a year is not 25 watts continuously; it is a compressor drawing far more, part of the time.
- Ignoring ambient temperature. Duty cycle rises with room temperature. A summer measurement and a winter measurement can differ enough to change which battery you buy.
- Forgetting that opening it costs energy. During an outage, a freezer left shut holds cold for a surprisingly long time. Every door opening spends some of that.
The equipment decision this leads to
- Solar generators and power stations — once you know your watt-hours per day, capacity is the number to shop on
- Portable inverter generators — if the outage is longer than a battery covers and you need to recharge or run directly
Related reading
Where these numbers come from
- U.S. EPA / U.S. Department of Energy, ENERGY STAR — Freezers
Primary source · read 2026-08-31
- An ENERGY STAR certified chest freezer uses about 215 kWh of electricity per year
- An ENERGY STAR certified upright freezer uses about 395 kWh of electricity per year
- U.S. Energy Information Administration — Use of energy explained: Energy use in homes
Primary source · read 2026-08-31
- The average U.S. household consumes about 10,500 kilowatthours of electricity per year
Common questions
How many watts does a freezer use?
ENERGY STAR figures put a certified chest freezer at about 215 kWh per year and a certified upright at about 395 kWh. Averaged over a year that is roughly 25 watts continuous for the chest and 45 for the upright. The compressor itself draws far more than that while it runs, and nothing while it is off.
What is the difference between running watts and surge watts?
Running watts is what the compressor draws while turning. Surge is the much larger spike as the motor starts, commonly several times the running figure and lasting a fraction of a second. An inverter or generator has to exceed the surge, not merely match the running watts, or it will trip every time the freezer cycles on.
Why does my freezer use less power than its label says?
A nameplate rating describes what the appliance can draw, not what it does draw. A freezer compressor runs for part of each hour and is off for the rest, so average consumption is far below the running figure. That share of the hour is the duty cycle, and it is the number a nameplate never tells you.
Do chest freezers use less electricity than uprights?
The ENERGY STAR figures say yes: about 215 kWh a year for a certified chest freezer against about 395 kWh for a certified upright. Cold air falls, so a chest loses less of it when opened than an upright does.
How long will a power station run my freezer?
It depends on your freezer's actual draw and duty cycle, which is why the calculator on this page asks you to supply them rather than assuming. As an order of magnitude, a 2,048 Wh power station running a freezer that averages 50 watts will last on the order of a day and a half — but ambient temperature, door openings and battery age all move that figure.