Ask Bob – April 2023

Bob Pierce headshot

Bob Pierce answers questions about energy efficiency, consumer products, and cooperative governance. He is Clearwater Power’s Chief Operating Officer and welcomes your questions on our Ask Bob page.

Q: How long will the food in my fridge be good during a power
outage?

A: There are a few variables that may affect this answer.

Assuming you have a modern refrigerator with a good door seal, and you are not opening the door during the power outage, the inside will likely stay cold enough to keep food safe for about 4 hours in a 70-degree room.

If the room is colder than 70 degrees, the refrigerator may remain at a food-safe temperature longer. If the temperature inside the fridge remains at 40 degrees or below, the food should be good.

Keep food safe before, during and after an power outage infographicInfographic The temperature of a freezer should be set to zero degrees or below. A freezer typically holds its temperature for 24 hours if it is half full and about 48 hours if it is completely full.

Because freezers can keep food safe longer during an outage, and run more efficiently when full, you should regularly freeze items you don’t plan to use immediately, and move items to the freezer in advance of a planned or anticipated outage. As recommended with your refrigerator, don’t open the doors during an outage.

One way to know for sure what is going on with the interior temperatures of your fridge and freezer is to buy a wireless temperature sensor. The cost for a set for a fridge and freezer starts at less than $30. Not only do they show the temperature inside without opening the door, most sensors also have an alarm that sounds when the temperature inside the fridge or freezer becomes unsafe.

This tool can help you know when food may be unsafe during an extended outage. It can also help you avoid losing expensive food products from an equipment failure that you may otherwise be unaware of until it’s too late.

If an outage lasts longer than your fridge can stay cold, you have a few options. If you have a portable generator, start it up outside where it has plenty of ventilation and run a heavy-duty extension cord from the generator to your refrigerator. Let the fridge run until it turns off, then move the cord to your freezer and do the same thing. If you don’t have a generator available, you may use dry or block ice to help keep the fridge or freezer temperatures safe.

Remember, refrigerators should be 40 degrees or below, and freezers should be zero degrees or below. Following a power outage, check the temperature inside your refrigerator or freezer. If the temperatures are within range, the food should be safe to eat.