We, at Sheridan Supply feel that there are many factors that determine when an air and water filters should be changed.
With water filters, you should follow the manufacturers directions. Are you on a well or do you have city water ? How much water is running through the system ? Do you have a whole house filter or a system beneath the sink ? If you have a faucet filter or are using a pitcher, you may want to upgrade. There are great systems out there that are easy to install and with the newer cartridge systems, they are very easy to replace because you just plug in a new cartridge !!!
Find that system which is best for you. Purchase a case of the replacements and keep them close to or under the sink. Apply a piece of masking tape to the filter housing or even to your cabinet door. Mark what date you installed the filter. Many replace after 3 months.
Change out your air filters too !!! How often the HVAC unit runs, your air quality, your humidity, if you have pets and if anyone in the household has allergies or illnesses all impact that decision. We all want the best for those around us.
Most of our customers purchase the 1”, 2” and 4” deep panel or pleated style filters. They change them out every 3 months and find it easy to just keep the case beside the equipment and keep the box closed.
In many commercial and industrial applications are a different story. Static pressure can be monitored and the filters can be changed when they reach their recommended final resistance in inches of water gauge.