This purifier is ideal for homeowners or renters with large open-concept living areas, master bedrooms, or multiple connected rooms up to 1900 sq ft, who prioritize comprehensive air quality. If you suffer from severe allergies, have pets, live in areas prone to wildfire smoke, or are sensitive to VOCs and odors, its high 1216 CADR smoke and advanced HEPA filtration for particles down to 0.1 micron make it a robust choice. Those seeking quiet operation for undisturbed sleep and the convenience of a smart sensor auto-adjusting fan speed will find the Alen 45i worth its higher investment for superior performance.

The Shark HC502 is perfect for individuals living in smaller apartments, single rooms, or offices up to 208 sq ft who seek a versatile, space-saving appliance. If you need a device that not only purifies the air but also provides heating in winter and acts as a fan in warmer months, this 3-in-1 unit is an excellent, more budget-friendly solution. It's ideal for those who value multi-functionality and smart sensor capabilities that automatically adjust to PM1/2.5/10 air quality without needing extensive coverage.