A phone call from my daughter recently reminded me why it’s important to know a few things before an emergency happens.
She lives in a college house with seven other girls, and their electricity suddenly went out. As it turned out, nobody realized they were responsible for paying the electric bill. Apparently, it hadn’t been paid since June. Oops!
One of her biggest concerns was the food in their refrigerator and freezer. How long would everything stay safe without electricity? Would they have to throw it all away?
That got me thinking about how much we depend on being able to look up answers whenever something goes wrong.
And that’s exactly why I’m building our SHTF Bible — a collection of practical information worth keeping on paper, just in case Google isn’t an option.
Today’s lesson? Three numbers everyone should remember when the power goes out: 4–48–24.
What Is the 4–48–24 Rule?
When the electricity goes out, your refrigerator and freezer can keep food at safe temperatures for a limited amount of time — as long as you keep the doors closed.
Here are the three numbers worth remembering:
4 HOURS — REFRIGERATOR
An unopened refrigerator will keep food cold for approximately four hours during a power outage.
48 HOURS — FULL FREEZER
A full freezer can maintain a safe temperature for approximately 48 hours if the door stays closed.
24 HOURS — HALF-FULL FREEZER
A half-full freezer can maintain a safe temperature for approximately 24 hours if the door stays closed.
The Most Important Thing? Keep the Doors Closed!
Every time you open the refrigerator or freezer, cold air escapes.
Resist the temptation to keep checking your food. Keeping those doors shut helps preserve safe temperatures for as long as possible.
Important: These times are guidelines, not guarantees. Use an appliance thermometer when possible. Discard refrigerated perishable food that has been above 40°F for four hours or more. Frozen food that still contains ice crystals or measures 40°F or below can generally be refrozen or cooked. Never taste food to decide whether it’s safe.
SHTF Bible Card #001: When the Power Goes Out
Blackout Essentials: A Few Things Worth Having
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Knowing the 4–48–24 rule is important, but having a few basic supplies can make a power outage much easier to manage.
Here are some practical items worth keeping on hand:
Refrigerator and Freezer Thermometers: These help you check actual food temperatures rather than guessing whether something is still safe.
Shop Refridgerator & Freezer Thermometers
Battery-Powered Lanterns: A reliable light source makes it easier to move around your home when the electricity is out.
Portable Power Banks: Keeping a charged backup battery available can help you stay connected when outlets aren’t working.
Insulated Coolers: A cooler and a supply of ice can help keep perishable foods cold during longer outages, provided you monitor their temperatures.
You don’t need to buy everything at once. Start with what you already have and build your emergency supplies over time.
Trusted Sources & Further Reading
Food safety matters, especially during an extended power outage. For additional guidance, visit:
Always check current food safety guidance rather than relying on appearance, smell, or taste alone.
Affiliate Disclosure
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