Review on Aprilaire 501 Replacment Electronic Purifier by Eric Trask

Replacing this particular filter is very difficult. It's not the filter's fault, it's the design of the mount it's placed in. Plan two days for this. The filter housing will most likely need to be hosed down and left to dry overnight. Installing the filter can take up to an hour for a beginner - around 15 minutes if you've done it before. However, if you don't want to pay a heating and cooling specialist to install it, buying and installing a filter here is a good idea.