MERV stands for Minimum Efficiency Reporting Value, and measures a filters’ efficiency in removing small particles. The higher the MERV rating, the more particles the filter can remove.
Refrigerator filters are made to reduce chlorine odors and tastes while reducing the amount of contaminants in your fridge water and ice. These filters remove the things that make your ice taste "off" or bad, and fit the Whirlpool and Thermador models, as well as other similar refrigerators.
Water capacity of the AquaFresh and Whirlpool filters are 400 gallons, while the capacity of the WaterSentinel is 300 gallons, making them last about six months under normal usage conditions. When you buy them in packs of three, you can save money by only making a purchase about once per year.
These fridge filters can put out about half a gallon per minute, and can replace many of the discontinued filter models. They can be installed relatively quickly by sliding into the grille of the ice maker on most fridge models, without using any tools. Pressure range is between 30 to 120 pounds per square inch and the filters have a temperature range of 33 to 100 degrees. Whenever water pressure slows down or you notice a red light on the indicator, you know it is time to replace the filter.