A study conducted by the Woolcock Institute of Medical Research found that the use of some vacuums was ineffective at allergy avoidance because it removed dust mite allergen from carpets in an inconsistent and incomplete manner. According to DentalPlans.com, studies show that vacuuming may in fact change the distribution of dust mite allergen within the carpet, rather than removing allergen from all depths equally — especially in older carpeting.

On the up side, the Woolcock study also revealed that vacuum cleaners with rotating brushes in the head removed more dirt and allergen from the carpets than those without. However, rotating brushes may kick up dust into the air if the suction is not strong enough or not operating properly. Vacuums with two or three layer bags also performed better than those with a single layer bag and vacuums with HEPA filtration were recommended around people with alergies.

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