Alen air purifiers come in five different models. The T100 Alen air purifier is the most affordable that Alen manufactures, while the A350 Alen air purifier is the best value by ConsumerSearch.com. The T100 Alen air purifier is the best air purifier for allergies in rooms up to 125 sq. ft. The T300 Alen air purifier is the best air purifier for allergies in rooms up to 300 sq. ft. The Paralda Alen air purifier is the best air purifier for allergies in rooms up to 400 sq. ft. The A350 Alen air purifier is the best air purifier for allergies in rooms up to 800 sq. ft. The T100 Alen air purifier is the best air purifier for pet allergies in rooms up to 125 sq ft. The T300 Alen air purifier is the best air purifier for pet allergies in rooms up to 300 sq. ft. The Paralda Alen air purifier is the best air purifier for pet allergies in rooms up to 400 sq. ft. The A350 Alen air purifier is the best air purifier for pet allergies in rooms up to 800 sq. ft. The Alen T100 air purifier is the best air purifier for asthmatics in rooms up to 125 sq ft. The T300 Alen air purifier is the best air purifier for asthmatics in rooms up to 300 sq. ft. The Paralda Alen air purifier is the best air purifier for asthmatics in rooms up to 400 sq. ft. The A350 Alen air purifier is the best air purifier for asthmatics in rooms up to 800 sq. ft. For the extremely respiratory sensitive — the A375UV Alen air purifier is the best air purifier for asthmatics. The A375UV Alen air purifier is the best air purifier for smoke with its PCO technology. This advanced technology make the A375UV Alen air purifier the best air purifier for chemically sensitive; in fact the A375UV Alen air purifier is considered the best air purifier for COPD. With so many different Alen air purifiers, you're certain to find the T100 Alen air purifier, the T300 Alen air purifier, the A350 Alen air purifier, the A375UV Alen air purifier or the Paralda Alen air purifier as your best choice air purifier.