these filters are designed for whole house use. the life of the filter will vary however this is a washable filter and normally can be washed 3 times giving you 18 months on average...******THE REGULAR PRICE IS $98.00, BUT IF YOU WANT TO BUY IN BULK AND SAVE MONEY THEN SELECT A LARGER QUANTITY OF FILTERS THROUGH THE DROP DOWN MENU BELOW.(, ADD 4 SAVE 10%, ADD 9 SAVE 15%, ADD 19 SAVE 20%, ADD 49 SAVE 35%!!!!!!!!!!!!