Quick answer: Yes. A 1,000 Wh station carries a certified refrigerator overnight, about 15 hours, which clears a twelve-hour night with room left. That figure assumes the ice maker is off — because the certified rating is measured with it disabled. NIST measured one cabinet making ice at 84 to 96 W, which cuts the night to eight or nine hours.
The runtime is not the interesting part. Every table on the internet, this site’s 1,000 Wh runtimes included, divides a battery by a refrigerator’s average draw and prints a number of hours. The number is right. What almost nobody says is that the average draw it uses was measured with a component switched off — one that, running, decides whether a 1,000 Wh station covers the night at all. For the wider decision, our power station sizing guide covers every tier.
The rating everyone quotes has the ice maker switched off
The figure this site uses for a refrigerator is 52.6 W, the median of 2,886 ENERGY STAR certified models. It comes from the federal test procedure at 10 CFR Part 430. And in that procedure, as NIST puts it in Technical Note 1697, automatic ice makers “are rendered inoperative during the regulated energy consumption test”.
That is not a loophole; it lets two refrigerators be compared on the same basis. But every runtime calculator on the internet is built on a refrigerator that is not making ice.
NIST measured the difference on four cabinets. On the top-mount unit, the same appliance drew 464.5 kWh a year with the ice maker disabled — 53.0 W, which is within half a watt of the certified median above, and a useful check that the median is not an artefact. With the ice maker producing, the same cabinet drew between 732 and 841.5 kWh a year, depending on which of NIST’s two calculation methods you take. That is 83.6 to 96.1 W, and an increase of 267 to 377 kWh a year attributable to ice alone.
The reason is not the freezing. It is the harvest. Freeing the cubes from the mould is done with an electric heater inside a freezer: NIST measured that heater at about 190 W for 90 seconds per batch, with a 28 W solenoid for ten seconds to refill the tray. A resistance heater fighting the compressor that is trying to keep the compartment cold is an expensive way to spend a battery.
| What you are running overnight | Draw | 1,000 Wh station | 2,000 Wh station |
|---|---|---|---|
| Refrigerator, ice maker off | 52.6 W | 15 hours | 30 hours |
| Refrigerator and chest freezer, ice maker off | 75.6 W | 10 hours | 21 hours |
| Refrigerator, ice maker producing | 84–96 W | 8–10 hours | 17–19 hours |
| Nothing at all — door simply kept shut | — | 4 hours | 4 hours |
Read the first and third rows together. At 1,000 Wh, switching the ice maker off is the difference between covering a twelve-hour night and falling short of it — and it costs nothing. In hours it recovers most of what the second thousand watt-hours would buy you, for free. On most units it is a wire arm you lift or a switch inside the compartment; the manual will say which.
Refrigerator overnight: how much of the night do you need to cover?
Less than all of it. The FDA puts it plainly: a refrigerator “will keep food cold for about 4 hours if it is unopened”, and a full freezer holds its temperature for “approximately 48 hours (24 hours if it is half full) if the door remains closed”.
Those two numbers reorganise the whole question. A full freezer does not need your power station overnight at all — it needs the door to stay shut, and it will still be frozen the following evening. The refrigerator is the only compartment a single night outlasts, and it is the smaller load. Whatever capacity you have, it should go to the fridge first.
It also means the four hours in the last row are yours before you spend a watt-hour: a twelve-hour night is not a twelve-hour draw. Judge it with an appliance thermometer rather than a clock — the FDA advises one in each compartment for exactly this, and its 40 °F line decides whether food stays or goes, not the hours elapsed.
One thing the chart cannot show: NIST’s ice-making figures were measured with the machine producing continuously, the test period ending when the storage bin filled. A bin that is already full stops the cycle. So 84 to 96 W is the upper bound, not a typical night — the real draw sits somewhere between that and 53 W, depending on how much ice your household got through that day. The point stands either way: it is a variable large enough to decide whether the night is covered, and it is the one variable you can change for free.
How we calculated this
Runtimes are nameplate watt-hours × 0.8 ÷ the draw. The 0.8 is our planning figure, taken from the runtimes one manufacturer publishes for its own product. The 52.6 W is the median of 2,886 certified refrigerators; the 84 to 96 W is NIST’s measurement of one cabinet and should be read as one cabinet, not a population. A nominal 1,000 and 2,000 Wh are used rather than any one product’s capacity.
Whether a given station will start a refrigerator is a separate question from whether it will run one, and a harder one: no appliance maker publishes a starting figure, and the compressor makers who do publish 3,146 to 4,626 VA. That gap is the subject of starting watts versus running watts, and it is settled more comfortably at 2,000 Wh than below it. No product was tested by us and none is recommended. Our method is described at how we test.
Before you rely on this overnight
A portable power station is a plug-in appliance. Do not wire one into your home’s circuits, and never feed a house through a wall socket — that is backfeeding and it can kill line workers. A transfer switch is electrician work.
Food that has been above 40 °F for four hours or more should be discarded, and the FDA is explicit that you never taste food to decide. If someone in the house depends on medical equipment, size it with the equipment supplier rather than from a table.
Frequently asked questions
What size power station do I need for a refrigerator overnight?
For energy alone, 1,000 Wh covers a twelve-hour night with the ice maker off, and roughly eight to ten hours with it producing. What actually decides the purchase is the surge rating, not the capacity: starting the compressor is the hard part, running it is not.
Should I turn the ice maker off during an outage?
On the arithmetic here, yes — it is the single largest saving available to you, and unlike buying a bigger battery it is free and takes a second. NIST attributes 267 to 377 kWh a year to ice production on the cabinet it measured, most of it spent on a heater melting the cubes loose.
Do I need to keep the freezer running too?
Probably not overnight. The FDA gives a full freezer approximately 48 hours with the door closed, and 24 if it is half full. A single night falls well inside that, so the capacity is better spent on the refrigerator, which the same guidance gives about four.
Why do other sites say I need 1,500 to 2,000 Wh?
Because they assume a refrigerator draws 100 to 125 W. That is roughly double the certified median, and it is unsourced wherever we have found it. It is also, coincidentally, the assumption that doubles the size of the station you are told to buy.
The short version
A 1,000 Wh station runs a refrigerator overnight. Switch the ice maker off first, leave the freezer shut, put a thermometer in the fridge, and spend the battery on the one compartment that cannot get through a night alone. Then size for the surge rather than the hours, because the hours were never the difficult part.
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.
