The longevity of ice blocks in the fridge without power depends on several factors, including the initial temperature of the fridge, the ambient room temperature, the insulation of the fridge, and the size and quantity of the ice blocks. Here are some general guidelines:
Well-insulated fridge with a full freezer: If your fridge is well-insulated and has a full freezer, the ice blocks can last for about 24 to 48 hours without power, assuming the fridge was at a relatively low temperature (close to freezing) before the power outage.
Less-insulated or partially filled fridge: If your fridge is less insulated or not fully stocked with items, the temperature inside can rise more quickly during a power outage. In such cases, the ice blocks might last for about 12 to 24 hours without power.
Larger ice blocks: Larger ice blocks tend to melt more slowly than smaller ones due to their lower surface area relative to their volume. So, if you have large ice blocks, they can help maintain a cooler temperature for a longer duration.
Cool room temperature: If the ambient room temperature is relatively cool, the ice blocks may last longer as they won't have to work as hard to maintain a low temperature.
It's essential to keep the refrigerator door closed as much as possible during a power outage to help retain the cold air inside. Opening the door frequently will cause the temperature to rise rapidly, reducing the ice blocks' effectiveness.
As a general rule, it's a good idea to have a backup plan in case of a prolonged power outage. If you know that an outage is likely, you can prepare by using a portable cooler with ice packs or dry ice to keep perishable items cold. Additionally, you can monitor the temperature inside the fridge with a thermometer to assess the safety of the food and ice blocks during an outage.
If the power outage is expected to be prolonged (more than a day), and you're concerned about food safety, it's best to transfer perishable items to a cooler with ice or seek alternative refrigeration options until the power is restored. When in doubt, discard any food or ice that you suspect may have reached unsafe temperatures during the outage to avoid foodborne illnesses.