When it comes to coolers, the R-value is a measure of how well the cooler will insulate your food and beverages. The higher the R-value, the better the cooler will be at keeping things cold. Most coolers have an R-value of around 2 to 4, which is good for keeping things cold for a few hours. However, if you want to keep things cold for a longer period of time, you'll need a cooler with a higher R-value. For example, coolers with an R-value of 8 or more will keep things cold for up to 24 hours.