As of 2015, a hot air furnace can be purchased from online retail stores, such as Home Depot and Lowes, as well as manufacturer websites, such as Rheem and Lennox. Manufacturer websites also typically provide a dealer or store locator for interested customers who want to shop for furnaces locally.
Online retail stores typically have a wider range of choice in terms of hot air furnaces and other products. On the Home Depot website, customers can choose from five different hot air furnace brands and narrow them down by price and heat rating. Manufacturer websites are limited in choice, but generally provide more product detail and other services, such as warranty information and related literature.