WW4 and WW5 Replacement Filters for WW4 and WW5 Wholehouse units

For the original WW4 and WW5 Wholehouse units we offer the Pre-filter which should usually be replaced once every 6 months and the Matrix Carbon Block filter. This filter should be replaced in the WW4 once a year for 3 people in the house and every 6 months for 6 people in the house.  The WW5 takes 2 main filters which should be replaced once a year for 6 people in the house and every 6 months for 12 people.