If you are not sure whether to buy an original or cheaper universal replacement fridge water filter, here are some guidelines that you should consider before purchasing:

1) Look out for the NSF logo. If the filter has one, you should be safe knowing that the filter correctly reduces the level of contaminants down to the certified level. Water purification companies pay a lot of money to NSF to have each filter model tested and certified. Once the product passes the NSF testing, companies are allowed to use the NSF logo on their certified products. Buying a universal filter without this seal of certification means that you can't be sure whether the contents of the water filter are beneficial or not. However, be aware that unfortunately there are some companies / manufacturers that use unauthorised NSF logos on their products. Therefore, if you have any doubts, visit the NSF website to check that the manufacturer and filter model is listed as certified.

2) Check the filter media used in the filter. Carbon is the primary substance used in water filters because activated carbon has the potential to adsorb many of the chemicals found in water. Activated carbon filters used for home water treatment typically contain either Granular Activated Carbon (GAC) or carbon block. Although both are very effective, carbon block filters generally have a higher contaminant removal ratio. With fridge water filters contains GAC, after some time water forms a channel (pushing the granular carbon to the side), and therefore allowing water to pass directly through the filter without filtration.

3) Check for the fridge water filter operating specifications. The description of a water filter should contain the following information: flow rate, operating temperature, operating pressure, service life, capacity and a type of medium it contains. This should at least be equal to the original filter. If not, you could find that the flow of water is greatly reduced, or in the worst case that the filter ruptures due to the water pressure of your mains supply.

4) Check the name of the manufacturer and country of origin to be sure that the manufacturer really exists and whether they are a reputable and regulated water purification manufacturer. This will avoid you buying any low cost universal filters.

To conclude you can safely buy cheaper universal replacement fridge water filters instead of the original ones but look for the main criteria mentioned above. If you are buying your fridge filter online make sure that the seller provides all the information, if not contact them to make sure that you are getting what you want.