The main difference between the Medify Air MA-40 and the Medify Air MA-25 air purifiers lies in their coverage area. As explained in this Medify Air MA-40 Air Purifier Review, the MA-40 is designed for medium to large-sized rooms, with an impressive coverage area of up to 1,300 square feet, making it suitable for bedrooms, living rooms, and offices. On the other hand, the Medify MA-25 is intended for smaller rooms, providing efficient air purification for spaces with fewer square feet. Both Medify Air Purifiers feature similar high-quality filtration systems, but the choice between them depends on the size of the room you need to purify.