How Long Can A Refrigerator Stay Cold Without Power?

If you're a new homeowner you likely have appliance questions, like what's the best refrigerator brand. The first time the power goes out, however, the question you'll likely be asking is how long a fridge can stay cold without power.

A refrigerator can generally keep food safely cold for about four hours after a power outage, provided its door stays closed. That is the widely used food-safety guideline from the FDA, and it applies to a refrigerator that was already operating normally before the outage began. Once the interior temperature rises above 40 degrees Fahrenheit for too long, bacteria can multiply quickly.

Several factors can shorten or extend the real-world result. A refrigerator in an air-conditioned kitchen will generally retain its temperature longer than one in a hot garage or sunlit room. A fully stocked unit also holds cold better than a mostly empty one because chilled food and drinks act as thermal mass. The best move during an outage is simple: Keep the refrigerator closed. A refrigerator thermometer can make the decision easier once power returns. If the interior stayed at or below 40 degrees Fahrenheit, refrigerated foods should remain safe.

If the outage reaches four hours, transfer perishables to a cooler packed with ice or frozen gel packs if possible. The FDA advises discarding refrigerated perishables that have been above 40 degrees for four hours or longer. Of course, if the fridge doesn't come back on even when you get power back, that's one of several signs you may need a new fridge.

The freezer side of the appliance has a much larger safety window. An unopened full freezer can keep food safely frozen for about 48 hours, while a half-full freezer can maintain safe temperatures for around 24 hours. That makes the freezer a useful source of cold during a lengthy outage, particularly if it contains densely packed frozen food.

A full freezer stays cold longer because frozen items function like ice packs. The more frozen mass inside, the slower the temperature rises. That also means homeowners can prepare for storm season by keeping containers of water frozen in unused freezer space. Besides helping the freezer retain its temperature, those containers can later be moved into a cooler to protect refrigerator items.

If an outage is likely to exceed four hours, move the most perishable refrigerator foods into a cooler with ice. Keep raw meat, dairy products, eggs, and leftovers cold first; condiments, unopened beverages, hard cheeses, butter, and many whole fruits and vegetables are generally less urgent. Avoid repeatedly opening the freezer while moving items around, since the goal is to preserve its cold reserve.

The easy numbers to remember are four, 24, and 48: about four hours for an unopened refrigerator, 24 hours for a half-full freezer, and 48 hours for a full freezer. A thermometer, a cooler, and a supply of ice can turn those basic limits into a far less stressful power-outage plan. For more helpful info, take a look at how our guide to how many amps a new refrigerator might require.