Furnace filters are available in a variety of stores, including hardware, home improvement, department and even drug stores. Individual manufacturers sell replacement filters for their own furnaces, and retailers list filters with online platforms such as Amazon.com and eBay.
In 2015, stores such as Ace hardware, Home Depot, Wal-Mart, Target and Walgreens all listed furnace filters in their inventory. The filters are available both online and in the store itself. However, a greater variety is available online. Some filters are universal for certain sizes of heaters, while others can only be used with specific brands.
Ace Hardware categorizes its furnace filters according to high efficiency and standard fiberglass in addition to brands. The filters are available for free in-store pick up, or they can be shipped for a fee.
The Wal-Mart website offers the option of filtering the results according to local availability. The site also advertises free in-store pick up. Several discounted and clearance items are available, sometimes being sold through outside retailers. Customers can choose to view only Wal-Mart's options, though.
Walgreens sells a limited number of furnace filters. However, the site offers an auto-reorder option that gives discounts to its members.
Amazon.com lists furnace filters being sold both by retailers and by individual sellers. In many cases the filters are listed with a discount. Sometimes customers can buy used filters.